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Theoretical versus Practical Energy: A Plea for More Transparency in the Energy Calculation of Different Rechargeable Battery Systems

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... Commercial LIBs are based on intercalation materials and have energy density <600 Wh· L −1 and specific energy <300 Wh·kg −1 at cell level [22], cycling performance <1000 cycles and C-rate capability <2C [23]. Additionally, there are still concerns regarding their safety, cost and sustainability that should be addressed by the next-generation battery systems for future automotive applications. ...
... Additionally, solid electrolytes will allow the voltage of Li-ion cells to extend beyond 5 V, as expected for oxide-and phosphate-based solid electrolytes [168]. These developments, together with the use of Li metal as an anode, will effectively increase the specific and volumetric energy of the cells [22]. However, state-of-the-art solid electrolytes still possess low ionic conductivity and poor electrode wetting, which limits their performance at room temperature but could be an advantage for applications at elevated temperatures [169]. ...
... It is generally set to 1.10-1.15 for LIBs to offset Li lost at the anode (graphite) [22] but new electrode combinations will require optimised N/P values to achieve good performances. Regarding slurry toxicity and cost, alternatives to 1-Methyl-2-pyrrolidinone (NMP) as processing solvent are needed. ...
Article
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Nowadays, batteries for electric vehicles are expected to have a high energy density, allow fast charging and maintain long cycle life, while providing affordable traction, and complying with stringent safety and environmental standards. Extensive research on novel materials at cell level is hence needed for the continuous improvement of the batteries coupled towards achieving these requirements. This article firstly delves into future developments in electric vehicles from a technology perspective, and the perspective of changing end-user demands. After these end-user needs are defined, their translation into future battery requirements is described. A detailed review of expected material developments follows, to address these dynamic and changing needs. Developments on anodes, cathodes, electrolyte and cell level will be discussed. Finally, a special section will discuss the safety aspects with these increasing end-user demands and how to overcome these issues.
... When the NPs start to form an alloy with lithium and undergo a large volume change, the anode can remain structurally intact because the highly conductive CNTs act as a flexible conductive wire mesh, allowing the electrochemically active nanoparticles to remain attached to the current collector of the anode and enhancing the electronic conductivity. Additionally, the fabrication path we propose herein avoids the extensive use of traditional solvents that are necessary during the regular electrode fabrication in LIBs industry, thus reducing the dead weight present in the state-of-the-art commercial anodes (15 to 20%).[45] Lithiation / delithiation capacities and Coulombic efficiency of SiNPs@VACNTs electrode (30 µm of VACNTs and 5 min deposition of Si) during 2000 cycles at C/20 and C/5 rate (a) and rate capability retention of the electrode obtained at different lithiation/ delithiation rates (b). ...
Article
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Silicon is one of the most promising anode materials for Lithium‐ion batteries. Silicon endures volume changes upon cycling, which leads to subsequent pulverization and capacity fading. These drawbacks lead to a poor lifespan and hamper the commercialization of silicon anodes. In this work, a hybrid nanostructured anode based on silicon nanoparticles (SiNPs) anchored on vertically aligned carbon nanotubes (VACNTs) with defined spacing to accommodate volumetric changes is synthesized. Achieving electrodes with good stability and excellent electrochemical properties remain a challenge. Therefore, we herein tune the silicon areal loading either through the modulation of the SiNPs volume at a fixed VACNTs carpet length or through the variation of the VACNT length at a fixed SiNPs volume. The low areal loading of SiNPs improves capacity stability during cycling but triggers large irreversible capacity losses due to the formation of the solid electrolyte interphase (SEI). By contrast, higher areal loading electrode reduces the quantity of the SEI formed, but negatively impacts the capacity stability. A higher gravimetric capacity and areal loading mass of silicon is achieved via an increase of VACNTs length without compromising cycling stability. This nanostructured electrode shows an excellent stability with reversible capacity of 1330 mAh g‐1 after 2000 cycles.
... 21 Many have recognized the chronic mismatch between academic reports and industrial metrics in various lithium-ion cells. 22 Gogotsi and Simon suggested that a factor of 4 to 12 must be considered when extrapolating the energy/power densities from the material level to the device level due to the composite nature of electrodes. 23 In this work, we estimate that this factor can potentially be reduced to ca. 2 by taking advantage of the solid electrode design that is free of any binder, conductive agent, and copper current collector (as detailed in Supporting Information). ...
Article
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In the race to increase lithium-ion cell manufacturing, labor and energy costs quickly ascend to become chief concerns for building new facilities, as conventional electrode designs need significant resources during fabrication. Complicating this issue is an empirical trade-off between environmental friendliness and ethical sourcing. To circumvent this paradox, modified cell designs that employ foils and textiles can significantly change manufacturing considerations if their simple construction can be matched with competitive performance. In this work, we demonstrate one possible cell design for a lithium-ion device that utilizes a fabric and a foil for the cathode and the anode, respectively. For the anode, a prelithiated aluminum foil is chosen, as the room-temperature solubility range of the LiAl phase is well-suited to uptake and release lithium, all while reducing energy or cost-intensive production steps. The cathode is composed of activated carbon fiber textiles, which offer a scalable path to realize sustainability. With such benefits, this device design can potentially change the calculus for the mass production of energy storage devices.
... The room that scientists can explore is less and less. Just like the energy density, a report shows that the energy density improve by less than 3% in the last 30 years [17,18]. So, taking this trend, it can be roughly predicted it will reach 400 kWh/kg. ...
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China is in a period of the energy transition; more renewable energy is used to replace coal which has caused more and more environmental issues. Researches on energy storage play a significant role in the government’s future sustainable development plans. In this article, four types of rechargeable batteries’ characteristics will be explored and their applications for grid-scale energy storage. The Lithium-ion battery is the most well-established with the less exploring room one. Then Nickel-metal hydride battery, due to the complexity of its reaction condition and electrode materials, still retains room for exploration after decades of development. Mn-Cu battery and Mn-H battery have the shortest development cycle and are mostly still in the experimental research stage. The rechargeable battery is one of the most promising energy storage technologies in the future, but there are many kinds of rechargeable batteries, only part of which can be applied to hydropower storage. In this article, four types of rechargeable batteries are listed in different development stages. By analyzing and comparing their performance, the feasibility of grid-level energy storage is summarized, and the future development direction of them is predicted.
... 3 A fundamental look into the Li deposition process can provide valuable insight into the working mechanism of LMBs and their shortcomings, thus paving the way to improving their performance and more widespread usage. [4][5][6] Despite considerable advancement in the understanding of the mechanisms involved in LMBs operation, [7][8][9] certain key issues are yet to be explored indepth, especially the early-stage nucleation process of Li on different substrates. ...
Article
The nucleation overpotential has been used by many researchers as an indicator of the energy required to form the Li nuclei during plating. Typically, a two-electrode system is used to measure the nucleation overpotential; this method, however, fails to show the contribution of working and counter electrodes separately. In this study, we have used a three-electrode configuration (three-dimensional nickel foam as working electrode, and lithium foil as both reference and counter electrode) to deconvolute the potential associated with each electrode during the galvanostatic Li electrodeposition to obtain a clear picture of nucleation overpotential. The results indicate that, in such a system, the main source of overpotential is the sudden drop in the potential of the counter electrode, which can be attributed to the extraction of Li from the surface of lithium metal. Moreover, unlike the first half-cycle, the nuclear overpotential is dominated by the working electrode in the second half-discharge cycle, which should account for a true nucleation overpotential of the system. This finding may aid in clarifying the origins of the experimental polarization and preventing researchers from misinterpreting it in terms of nucleation overpotential.
... Y. Gogotsi and P. Simon suggest that a factor of 4 to 12 has to be considered when extrapolating the energy/power densities from the material level to the device level due to the composite nature of electrodes. [13,14] In this work, we estimate that this factor can safely be reduced to 2 by taking advantage of the solid electrode design that is free of binder, conductive agent, and current collector (dense copper), supporting the competitiveness of this technology (as detailed in SI). ...
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In the race to improve lithium-ion cell manufacturing, societal impact is a chief concern as significant resources are required to meet increasing demands. Modified cell designs which employ foils and textiles with simplified constructions offer a scalable path to realize sustainability. Here we demonstrate the novel design for a lithium-ion energy storage device which utilizes a pre-lithiated aluminum foil anode and an activated carbon fiber cathode avoiding energy or cost-intensive production steps.
... That works for us for several years and does not need to be replaced, while if we use materials whose electron transfer reaction is not reversible, the built-in battery will be a non-rechargeable battery and will need to be replaced. The reversibility of a reaction means that the reaction in the opposite direction can also be performed [227][228][229][230]. ...
Article
This paper presents a review of literature that introduces the properties and applications of Magnetorheological fluids(MRFs). first, magnetic particles (iron or cobalt), base fluids(oil (mineral-synthetic) or water), and how to prepare magnetorheological fluids are discussed. Then, in the continuation of this research, considering that magnetorheological fluids are smart and soft liquids, the methods of stability and properties (viscosity, hysteresis loop, Shear yield stress, etc) Of these magnetorheological fluids are discussed. Due to the different properties of Magnetorheological fluids, the behavior of these fluids in different states is discussed. These intelligent fluids change their properties when exposed to an external magnetic field. The most important and obvious feature of magnetorheological fluids is their reversibility from liquid to semi-solid state or vice versa in the Presence or the absence of a magnetic field in a fraction of a second. This change in state and properties is known as the magnetorheological effect. This effect depends on various factors, such as the concentration of magnetic particles, the distribution of magnetic particles, the strength of the magnetic field, additives, and so on. The low magnetic effect and instability of magnetorheological fluids are the most important problems against their widespread use in modern industries. According to research, carbonyl iron particles are the most promising particles for the dispersed phase in MRF. The choice of carbonyl iron particles contributes to their high saturation magnetism, relatively low cost, low coercion, and widespread availability. Finally, according to the different properties and behaviors of these fluids, different applications of magnetorheological fluids are discussed. MRF-based control systems are increasingly used in engineering applications such as rheological magnetic electrolytes in batteries, anti-lock braking systems, magnetic clutches, vibrating dampers, shock absorbers, control valves, and various types of vibrating dampers. One of the newest applications of magnetic fluids is the magneto-rheological electrolyte. The use of MRFs in batteries introduces a new class of magnetic field-sensitive electrolytes that has the potential to increase impact resistance, safety, thermal conductivity, and energy storage in electronic devices through reversible active switching electrolyte mechanical properties.
... Due to their high level of technological maturity combined with a good compromise between energy density, power, energy efficiency, lifetime, and costs, rechargeable lithium-ion batteries (LIBs) are a prime choice for mobile energy storage, which includes electro-mobility as the largest future market. [2][3][4] Ni-rich LiNi 1 À x À y Co x Mn y O 2 (NCM) layered oxide materials with Ni contents of 60 to 80 % are commercially available cathode active materials to satisfy those needs and therefore enable extensive market penetration of EVs. [5][6][7] The main advantage of increasing the Ni content lies in an increased energy density on the material level (higher de-lithiation capacity at the same charge cut-off potential) and a reduced content of costly and toxic cobalt. ...
Article
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Ni-rich layered oxide cathodes are promising candidates to satisfy the increasing energy demand of lithium ion batteries for automotive applications. Aqueous processing of such materials, although being desirable to reduce costs and improve sustainability, remains challenging due to the Li+/H+ -exchange upon contact with water, resulting in a pH increase and corrosion of the aluminum current collector. Herein, an example for tuning the properties of aqueous LiNi0.83Co0.12Mn0.05O2 electrode pastes using a lithium polyacrylate-based binder to find the “sweet spot” for processing parameters and electrochemical performance is given. Polyacrylic acid is partially neutralized to balance high initial capacity, good cycling stability and the prevention of aluminum corrosion. Optimized LiOH/polyacrylic acid ratios in water are identified, showing comparable cycling performance to electrodes processed with polyvinylidene difluoride requiring toxic N-methyl-2-pyrrolidone as solvent. This work gives an exemplary study for tuning aqueous electrode pastes properties aiming towards a more environmentally friendly processing of Ni-rich cathodes.
... Rechargeable lithium ion batteries (LIBs) are the technology of choice for electro-mobility because of their high level of technological maturity combined with a good compromise between energy density, power, energy efficiency, lifetime, and costs. [2][3][4] Ni-rich LiNi1−x−yCoxMnyO2 (NCM) layered oxide materials with Ni contents of 60 to 80% are commercially available candidates for the positive electrode (=cathode) to satisfy those needs and therefore enable extensive market penetration of EVs. [5][6][7] The main advantages of increasing the Ni content lies in an increased energy density on material ...
Article
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Ni‐rich layered oxide cathodes are promising candidates to satisfy the increasing energy demand of lithium ion batteries for automotive applications. Thermal and cycling stability issues originating from increasing Ni contents are addressed by mitigation strategies such as elemental bulk substitution (“doping”) and surface coating. Although both approaches separately benefit the cycling stability, there are only few reports investigating the combination of two of such approaches. Herein, the combination of Zr as common dopant in commercial materials with effective Li2WO4 and WO3 coatings is investigated with special focus on the impact of different material processing conditions on structural parameters and electrochemical performance in NCM || graphite cells. Results indicate that the Zr4+ dopant diffusing to the surface during annealing improves the electrochemical performance compared to samples without additional coatings. This work emphasizes the importance to not only investigate the effect of individual dopants or coatings but also the influences between both.
... Li metal anodes provide approximately 50% higher battery energy density than do conventional graphite anodes [71]. In solid-state batteries, Li metal anodes can reduce space-weight requirements while guaranteeing a high energy density [72]. Moreover, Li metal anodes are more chemically stable against SSEs than are liquid-based electrolytes, which addresses most negative effects that conventionally occur in liquid batteries, such as dendrite formation-induced safety concerns [8]. ...
Article
All-solid-state batteries (ASSBs) offer great promise as a next-generation energy storage technology with higher energy density, wider operating temperature range, and improved safety for electric vehicles. ASSBs employing lithium metal anodes (Li), sulfide-based solid-state electrolytes (SSE), and Ni-rich layered transition metal oxide cathodes (LiMO2, M = Ni, Mn, Co, Al) are particularly promising due to its superior electrochemical performance compared to other solid-electrolyte systems. However, the battery cycle life at high cathode mass loading and high current is still limited because the failure mechanism is not fully understood. Lithium dendrite growth at the anode or inside a solid electrolyte still represents as a serious risk of cell failure. Interfacial resistance increases attributed to electrolyte decomposition and interfacial void formation at both cathode−electrolyte and anode−electrolyte interfaces lead to gradual capacity fading. In this Review, we present the fundamental challenges and recent scientific understandings of each component in ASSBs. The novel diagnostic tools for these components, especially the interfaces buried under the surface that are often hard for characterization are mainly examined. Finally, we offer a perspective for future research directions. We hope this Review will provide a timely snapshot of state-of-the-art research progress in ASSBs to accelerate the development of ASSBs.
... Lithium-ion batteries (LIBs) represent the most promising electrical energy storage system for mobile applications due to their superior properties compared to other secondary batteries [1][2][3]. Consequently, sales figures of LIBs increased drastically in recent years whilst fields of application diverged [4,5] Since then, and despite several recent innovative approaches, the recycling of used LIBs has fallen short of expectations, and a closed industrial recycling loop has not been established [6][7][8][9]. three metals. ...
Article
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The lithium-ion battery is the most powerful energy storage technology for portable andmobile devices. The enormous demand for lithium-ion batteries is accompanied by an incompleterecycling loop for used lithium-ion batteries and excessive mining of Li and transition metals.The hyperaccumulation of plants represents a low-cost and green technology to reduce environmentalpollution of landfills and disused mining regions with low environmental regulations. To examinethe capabilities of these approaches, the hyperaccumulation selectivity of Alyssum murale for metalsin electrode materials (Ni, Co, Mn, and Li) was evaluated. Plants were cultivated in a conservatoryfor 46 days whilst soils were contaminated stepwise with dissolved transition metal species via theirrigation water. Up to 3 wt% of the metals was quantified in the dry matter of different plant tissues(leaf, stem, root) by means of inductively coupled plasma-optical emission spectroscopy after 46 daysof exposition time. The lateral distribution was monitored by means of micro X-ray fluorescencespectroscopy and laser ablation-inductively coupled plasma-mass spectrometry, revealing differentstorage behaviors for low and high metal contamination, as well as varying sequestration mechanismsfor the four investigated metals. The proof-of-concept regarding the phytoextraction of metals from LiNi0.33Co0.33Mn0.33O2 cathode particles in the soil was demonstrated.
... In view of their high energy densities, absence of memory effects, and high round-trip energy efficiencies, conventional lithium-ion batteries (LIBs) are widely used on scales ranging from compact electronic devices to grid systems [8,9] but are currently reaching their maximal capacity, as their specific/volumetric energy densities are limited by the use of heavy metal-based active host materials. [10,11] The use of Li as a high-energy active anode material is a possible solution to this problem, as this metal exhibits a high theoretical capacity of ≈3860 mAh g −1 and a low redox potential (−3.040 V vs the standard hydrogen electrode). [12,13] However, the Li-metal anode (LMA) has some fatal drawbacks originating from highaspect-ratio metal growth, e.g., continuous electrolyte consumption, Coulombic efficiency (CE) reduction, elevated cell polarization due to side reactions producing dead Li, and safety issues caused by electrode short-circuiting. ...
Article
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Although the lithium-metal anode (LMA) can deliver a high theoretical capacity of ≈3860 mAh g-1 at a low redox potential of -3.040 V (vs the standard hydrogen electrode), its application in rechargeable batteries is hindered by the poor Coulombic efficiency and safety issues caused by dendritic metal growth. Consequently, careful electrode design, electrolyte engineering, solid-electrolyte interface control, protective layer introduction, and other strategies are suggested as possible solutions. In particular, one should note the great potential of 3D-structured electrode materials, which feature high active specific surface areas and stereoscopic structures with multitudinous lithiophilic sites and can therefore facilitate rapid Li-ion flux and metal nucleation as well as mitigate Li dendrite formation through the kinetic control of metal deposition even at high local current densities. This progress report reviews the design of 3D-structured electrode materials for LMA according to their categories, namely 1) metal-based materials, 2) carbon-based materials, and 3) their hybrids, and allows the results obtained under different experimental conditions to be seen at a single glance, thus being helpful for researchers working in related fields.
Article
Aqueous batteries based on iodine conversion chemistry have emerged as an appealing electrochemical energy storage technology due to their intrinsic fast conversion kinetics, ideal redox potential, and high specific capacity. However, several hurdles of active iodine like poor thermal stability, inferior electrical conductivity, and polyiodide shuttling need to be overcome before a real breakthrough and their wide application. Over the past decades, researchers around the world have dedicated enormous efforts to tackling the above obstacles. In this review, a systematic summary with regard to recent advances in aqueous iodine-based static batteries (AISBs) is presented. It begins with an introduction of iodine's fundamental physicochemical properties, particularly focusing on the analysis of iodine conversion chemistry, and discussing the corresponding challenges by category. Furthermore, the coping strategies in terms of cathode host selection, electrolyte optimization, separator engineering, and suitable anodes are in-deeply discussed, and the key parameters and work principles are analyzed. The final section shares the thoughts on the emerging research opportunities and future directions in advancing AISBs.
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Electrode processing and performance strongly depend on the active material. Maximizing the active material content of positive composite electrodes enables low cost and high energy density. However, this maximization cannot reach 100%, as composite electrodes additionally consist of binder to provide mechanical integrity and conductive additive to enhance electronic conductivity, which in combination create a flexible porous microstructure for appropriate electron and lithium transport. In this study, the influence of three positive active material classes, layered oxide LiNi0.6Mn0.2Co0.2O2, spinel-type LiMn2O4 and olivine-type carbon-coated LiFePO4, were investigated regarding the optimum amount of polyvinylidene difluoride as binder and carbon black as conductive additive to achieve high mechanical stability as well as high electronic and ionic conductivity within composite electrodes. Formulation optimization was conducted and compared to a reference electrode formulation with regard to physical, mechanical, electronic and electrochemical properties. In a first step, the binder amount was optimized for each active material class by varying the ratio of binder content to surface area of the solid electrode components. In a second step, the critical conductive additive content was determined. Overall, this strategy allows to decipher material class dependent optimized electrode formulations for high energy density composite electrodes with maximized active material content.
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Two-dimensional (2D) Ni-based materials have attracted considerable attention due to their distinctive properties, including high electro-activity, large specific surface areas, controllable chemical compositions, and abundant forms of composite materials. Over the last decade, there has been increasing research interest in constructing advanced 2D Ni-based nanomaterials possessing short and open channels with efficient mass diffusion capability and rich accessible active sites for electrochemical energy storage (EES). Herein, the recent advances in developing emerging 2D Ni-based materials involving Ni-based oxides, sulfides, phosphides, selenides, hydroxides, metal-organic framework (MOF), and Ni-rich layered oxides (LiNixMyM′zO2/NaNixMyM′zO2) for EES is reviewed. After a brief summary of crystal structures and synthetic methods of 2D Ni-based materials, design strategies for improving electrochemical performances of 2D Ni-based materials are described in detail through vacancy creation, heteroatoms doping, and 3D nanostructures. Afterward, their applications as electrode materials for EES including supercapacitors, alkali (Li, Na, K)-ion batteries, and multivalent metal (Zn, Mg, Ca)-ion batteries are discussed. This review also discusses the charge storage mechanisms of 2D Ni-based materials by various advanced characterization methods. Finally, the current challenges and research outlook of 2D Ni-based materials toward high performance EES devices are presented.
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Owing to its high capacity, silicon (Si) is a promising anode for meeting the escalating need for batteries with high energy density. Nonetheless, the substantial volumetric variation generated by lithiation/delithiation often results in the pulverization of Si, which substantially lowers its cycle stability. Graphene/graphene nanosheets (GNSs) with higher electrical conductivity and mechanical strength are anticipated to overcome these obstacles when employed as the coating matrix of silicon. Unfortunately, the majority of [email protected] composites are not manufactured in situ, so that graphene is hardly to entirely encapsulate Si.The low-quality coating leads to the exposure of Si after cycles, resulting in a short cycle life. Herein, graphene nanosheets encapsulated silicon nanospheres ([email protected]) are synthesized in situ using a radio-frequency (RF) thermal plasma system, in which graphene and Si have strong interfacial chemical interactions. Further, free-standing [email protected]/reduced graphene oxide ([email protected]/rGO) paper was prepared using graphene oxide (GO) as a special ‘binder’. When [email protected]/rGO paper is directly used as anode electrodes, it demonstrates a high reversible capacity (2270 mAh g⁻¹ at 0.2 A g⁻¹), outstanding rate performance (1569 mAh g⁻¹ at 5.0 A g⁻¹) and ultra-stable cycle performance (capacity retention of 98.55% for 2000 cycles at 3.0 A g⁻¹).
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Silicon suboxide (SiOx) is considered a promising substitute for silicon (Si) anode materials in lithium-ion batteries due to its high specific capacity (>2200 mAh g⁻¹) and improved cycling performance. However, its volume expansion (∼200%) and low conductivity cannot be ignored. Here, inspired by earbuds, we design and mass synthesize (240 g h⁻¹) the earbuds-like three-dimensional SiOx nanonetworks (3D-SiOx NNs) by a radio-frequency thermal plasma (RF-plasma) system. The spray drying technology is used to further accelerate the winding of 3D-SiOx NNs to prepare micron-sized multi-hierarchical earbuds-ball-like SiOx/C (E-SiOx/C) with enhanced elasticity and high tap density. As anodes, E-SiOx/C exhibits the high gravimetric/volumetric specific capacity of 1790 m Ah g⁻¹/1137 m Ah cm⁻³ and excellent rate cycling performance (1480 m Ah g⁻¹ at 2.0 A g⁻¹ for 700 cycles). In addition, full battery constructed with LiNi0.5Co0.2Mn0.3O2 cathode exhibit high gravimetric energy density of 530.9 Wh kg⁻¹ and impressive cycling performance (513.9 Wh kg⁻¹ for 100 cycles), manifesting great promise for the application of high-performance batteries.
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Silicon (Si)-based materials have been considered as the most promising anode materials for high-energy-density lithium-ion batteries because of their higher storage capacity and similar operating voltage, as compared to the commercial graphite (Gr) anode. But the use of Si anodes including silicon-graphite (Si-Gr) blended anodes often leads to rapid capacity decay in Si-Gr/LiNixMnyCozO2 (x+y+z=1) full cells, which has been attributed to surface instability of the Si component. In addition to stabilizing the surface, this work investigates the potential of the Si-Gr blended anodes in a full-cell configuration and its impact on the capacity contribution from active components. Using dQ/dV plots of the full cells, a powerful but simple-to-implement differential potential approach is developed to decouple the capacity contribution and degradation from the graphite and silicon components. Data collected from three-electrode cells confirm the results from the differential potential approach, which suggests a voltage slippage to a higher voltage at the blended anode side. The voltage slippage causes a reduced utilization of the Gr component and exacerbates side reactions between the Si-Gr anode and carbonate electrolytes. Furthermore, based on these failure mechanisms, we adopted a mitigation strategy to tune the open circuit voltage of the prelithiated anode while stabilizing the surface. As a result, the full cells with the modified Si-Gr anodes (mass loading, 2.5 mAh/cm²) offer a highly reversible full-cell energy density of 390 Wh/kg (based on the mass of both anode and cathode materials in a full cell) with a cycling CE of 99.9% over 200 cycles.
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Lithium-ion batteries (LIBs) exhibiting high capacity and energy density are in high demand in emerging markets such as electric vehicles and energy storage systems. However, these LIBs often show intrinsic shorter cycle life and higher risk of short circuit, which may result in thermal runaway and explosion. This work reviewed those polymers employed to improve cycling performance and safety of LIBs. First, some novel separator membranes, which prevent the direct contact of cathode with anode to induce disastrous short circuit, were developed with an aim at imparting safety to LIBs. For example, composite separators comprising ceramic and polymer show higher abuse tolerance for LIBs. Surface modification of the cathode active materials by polymers (e.g., polyimide (PI)) results in greatly enhanced electrochemical performance of LIBs, especially for layered LiNixCoyMnzO2. Another unique technology was developed, which involves coating reactive oligomer/polymer on the particle surface of cathode active materials to effectively limit the probability of short circuit and, eventually, thermal runaway of cells in an abusive environment. The fundamental mechanisms of the secondary oligomer/polymer reaction to form a dense highly cross-linked film on the pellet surface to inhibit thermal runaway were then discussed. This was followed by the last topic on polymer coated anodes used to suppress Li dendrite formation at the anode surface. Li dendrites may cause short circuit and capacity fading during cycling in LIBs. Some representative polymers including PI, polyurea and polycyanoacrylate that can greatly inhibit dendrite formation at anode surface were discussed.
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A novel solvating ionic liquid (SIL), N-methyl N-oligo(ethylene oxide)pyrrolidinium bis(fluorosulfonyl)imide (Pyr1,(2O)7FSI) was synthesized and used to prepare binary and ternary liquid electrolytes with LiFSI as conducting salt and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TTE) as a non-solvating low viscosity co-solvent. Thereby, the binary superconcentrated liquid electrolyte (i.e., 6.8m LiFSI in Pyr1,(2O)7FSI) reaches a Li⁺ ion transference number of 0.25 ± 0.02. To enhance the ionic conductivity and separator wetting, the binary electrolyte was mixed with TTE leading to local superconcentrated Li⁺ ion solvation structures as shown by Raman measurements. These ternary electrolytes exhibit improved wettability, excellent safety and allow cycling in NMC622||Li cells and Cu||Li cells with Coulombic efficiencies of up to 99.9% and 98.5%, respectively, and a capacity retention of 84% for NMC622||Li cells with the electrolyte 2.0m LiFSI, Pyr1,(2O)7FSI:TTE (1:1 wt%) after 100 cycles vs. a cell failure after 35 cycles for the state-of-the-art containing IL N-butyl-N-methylpyrrolidinium FSI electrolyte.
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This paper presents the electrochemical performance and characterization of nano Si electrodes coated with titanicone (TiGL) as an anode for Li ion batteries (LIBs). Atomic layer deposition (ALD) of the metal combined with the molecular layer deposition (MLD) of the organic precursor is used to prepare coated electrodes at different temperatures with improved performance compared to the uncoated Si electrode. Coated electrodes prepared at 150 °C deliver the highest capacity and best current response of 1800 mAh g ⁻¹ at 0.1 C and 150 mAh g ⁻¹ at 20 C. This represented a substantial improvement compared to the Si baseline which delivers a capacity of 1100 mAh g ⁻¹ at 0.1 C but fails to deliver capacity at 20 C. Moreover, the optimized coated electrode shows an outstanding capacity of 1200 mAh g ⁻¹ at 1 C for 350 cycles with a capacity retention of 93%. The improved discharge capacity, electrode efficiencies, rate capability and electrochemical stability for the Si-based electrode presented in this manuscript are directly correlated to the optimized TiGL coating layer deposited by the ALD/MLD processes, which enhances lithium kinetics and electronic conductivity as demonstrated by equivalent circuit analysis of low frequency impedance data and conductivity measurements. The coating strategy also stabilizes SEI film formation with better Coulombic efficiencies (CE) and improves long cycling stability by reducing capacity lost.
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Ultrathin devices are rapidly developing for skin-compatible medical applications and wearable electronics. Powering skin-interfaced electronics requires thin and lightweight energy storage devices, where solution-processing enables scalable fabrication. To attain such devices, a sequential deposition is employed to achieve all spray-coated symmetric microsupercapacitors (μSCs) on ultrathin parylene C substrates, where both electrode and gel electrolyte are based on the cheap and abundant biopolymer, cellulose. The optimized spraying procedure allows an overall device thickness of ≈11 µm to be obtained with a 40% active material volume fraction and a resulting volumetric capacitance of 7 F cm⁻³. Long-term operation capability (90% of capacitance retention after 10⁴ cycles) and mechanical robustness are achieved (1000 cycles, capacitance retention of 98%) under extreme bending (rolling) conditions. Finite element analysis is utilized to simulate stresses and strains in real-sized μSCs under different bending conditions. Moreover, an organic electrochromic display is printed and powered with two serially connected μ-SCs as an example of a wearable, skin-integrated, fully organic electronic application.
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Solid lithium-sulfur batteries (SLSBs) show potential for practical application due to their possibility for high energy density. However, SLSBs still face tough challenges such as the large interface impedance and lithium dendrite formation. Herein, a high-performance SLSB is demonstrated by using a fiber network reinforced Li6.75La3Zr1.75Ta0.25O12 (LLZTO) based composite solid electrolyte (CSE) in combination with sulfurized polyacrylonitrile (SPAN) cathode. The CSE consisting of an electrospun polyimide (PI) film, LLZTO ionically conducting filler and polyacrylonitrile (PAN) matrix, which is named as PI-PAN/LLZTO CSE, possesses high room-temperature ionic conductivity (2.75 × 10−4 S/cm), high Li+ migration number (tLi+) of 0.67 and good interfacial wettability. SPAN is utilized due to its unique electrochemical properties: reasonable electronic conductivity and no polysulfides shuttle effect. The CSE enables a highly stable Li plating/stripping cycle for over 600 h and good rate performance. Moreover, the assembled SLSB exhibits good cycle performance of accomplishing 120 cycles at 0.2 C with the capacity retention of 474 mAh/g, good rate properties and excellent long-term cycling stability with a high capacity retention of 86.49% from 15th to 1,000th cycles at 1.0 C. This work rationalizes our design concept and may guide the future development of SLSBs.
Article
Understanding the nature of ion transfer at the interface between Li metal and solid electrolytes (SE) is essential for further optimization of all-solid-state Li-ion batteries. Thus, the Li transfer across the SE|Li metal interface is investigated by means of ab initio calculations based on density functional theory in this work. The aluminum-doped garnet Li6.25Al0.25La3Zr2O12 (LLZO) is considered as a model SE due to its practical stability against Li metal. A low-energy interface model in bicrystal geometry is constructed and investigated by nudged elastic band calculations as well as ab initio molecular dynamics (AIMD) simulations. In order to distinguish between interface and bulk transport in the AIMD simulations, a post-processing protocol is developed. We find that the activation energies and diffusivities of Li are comparable in bulk LLZO and across the interface, substantiating that the interface kinetics are not rate-limiting. Moreover, electronic structure analysis indicates that charge transfer occurs gradually. Finally, Al3+ loss of LLZO at the interface rationalizes the experimentally observed phase transition from cubic to tetragonal observed close to Li metal contacts.
Article
For a successful transition from internal combustion engines to electric vehicles and from conventional power plants to renewable energy supply, battery technology plays a vital role. Accordingly, battery research and development (R&D) efforts have been increased considerably over the past decades, particularly regarding materials and cell chemistries to further improve the electrochemical performance of lithium ion batteries. The impetus behind such massive R&D has been the replacement of metallic lithium anodes, a notorious for potentially catastrophic shorting by lithium metal dendrites. However, despite the promise of a step improvement in energy density outperforming established LIB technology, the commercial introduction of cells with alternative anode materials in the mass market is slow. Against this backdrop, the aim of the present study is to provide an overview of current developments in the academic and industrial research arena, summarising the historical development of scientific literature and patent landscape beyond established anode materials. The study identifies and critically reviews tin, silicon, silicon oxide, aluminium and titanium-based anode materials as promising pathways to develop high-energy density next-generation LIBs.
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Rechargeable Li-based battery technologies utilising silicon, silicon-based, and Si-derivative anodes coupled with high-capacity/high-voltage insertion-type cathodes have reaped significant interest from both academic and industrial sectors. This stems from their practically achievable energy density, offering a new avenue towards the mass-market adoption of electric vehicles and renewable energy sources. Nevertheless, such high-energy systems are limited by their complex chemistry and intrinsic drawbacks. From this perspective, we present the progress, current status, prevailing challenges and mitigating strategies of Li-based battery systems comprising silicon-containing anodes and insertion-type cathodes. This is accompanied by an assessment of their potential to meet the targets for evolving volume- and weight-sensitive applications such as electro-mobility.
Article
Sluggish solid-state K⁺-migration kinetics and electrode material degradation represent two critical issues facing K-ion batteries. Here we report a new inorganic-open-framework (IOF) compound K0.76V0.55Nb0.45OPO4 (KVNP, synthesized through aliovalent substitution) which, as a bifunctional electrode material, simultaneously mitigates these issues on both anode and cathode sides. The distinctive IOF crystal structure enables a low K⁺-migration energy barrier (0.16 eV) even surpassing the Li⁺ counterpart in state-of-the-art LiCoO2/LiFePO4 (0.21/0.55 eV) and consequently achieves fast-charging capability and high energy efficiency. Equally important, KVNP undergoes exceptionally small lattice-volume changes upon cycling (7.1% on anode and 3.1% on cathode, versus 10% for graphite anode and 6.8% for LiFePO4 cathode in commercial Li-ion batteries). This intrinsic low-strain feature ensures high structural stability against K⁺-ion (de)intercalation and ultralong cycle lives of > 18 months for both KVNP anode and cathode (versus < 3 months for previously reported IOFs). Aliovalent substitution in IOFs may pave a way for the exploration of fast-charging and long-lifespan K-ion batteries.
Article
Unstable solid electrolyte interphase between lithium metal and electrolyte results in low coulombic efficiency and limited cycle life, which hinder the utility of lithium metal anode. Besides, how to settle the cathode material corrosion in practical lithium metal batteries is also a key challenge. Here, lithium 2 trifluoromethyl-4,5-dicyanoimidazolide (C6F3LiN4) is reported as valid electrolyte additive for bi-electrode protective films formation in practical Li metal-based batteries. The C6F3LiN4 plays distinct functions in bi-electrode interface, it attributes to robust F, N-rich polymer interphase layer on the cathode which effectively protect the cathode from deterioration. And it promotes the even distribution of LiF and polycarbonate species on anode and prevent the formation of Li dendrites. The symmetric cell of C6F3LiN4 exhibits stable cycling performance with 1 mA cm⁻² (700 h). In addition, the improvement in the Li metal deposition uniformity has been confirmed by atomic force microscope and simulation. Benefiting from the synergistic enhanced stability and uniformity of electrode interphase, the LiNi0.5Co0.2Mn0.3O2 || Li metal battery with C6F3LiN4 can maintain high capacity retention of 82.6% after 400 cycles. Importantly, the Li metal pouch battery pairing high-loading cathode (16.12 mg cm⁻²) also deliver longer cycle life, validating its feasibility in practical applications.
Article
Lithium (Li)-metal is considered as promising anode material for high-energy-density rechargeable batteries, although its application is hampered by inhomogeneous Li deposition and dendritic Li morphologies that could eventually result in contact losses of bulk and deposited Li as well as cell short circuits. Based on theoretical investigations, recent works on polymer electrolytes particularly focus on the design of single-ion conducting electrolytes and improvement of bulk Li⁺ transport properties, including enhanced Li⁺ transference numbers, ionic conductivity, and mechanical stability, thereby affording safer and potentially “dendrite-free” cycling of Li-metal batteries. In the present work, it is revealed that the spatial microstructures, localized chemistry, and corresponding distributions of properties within the electrolyte are also decisive for achieving superior cell performances. Thus, targeted modification of the electrolyte microstructures should be considered as further critical design parameters for future electrolyte development and to actually control Li deposition behavior and longevity of Li-metal batteries.
Article
Li dendrite growth and corresponding parasitic reactions are inherent vulnerability of lithium metal anodes, limiting practical adoption. Here, we report a stable artificial solid electrolyte interphase (SEI) layer consisting of Li2Se and LiCl with high Li ion conducting and insulating properties fabricated through a facile and low-cost approach. The designed artificial SEI layer on Li blocks direct contact with the electrolyte and enables dendrite-free Li plating through the artificial SEI layer. With these benefits, Li anodes modified with an artificial SEI show dendrite-free Li plating behaviors with a lower porosity of 30% compared to that of bare Li (43%) at a high current density of 5.0 mA cm⁻² and a high capacity of 40 mAh cm⁻². In addition, modified anodes exhibit stable cyclability with lower overpotentials in Li symmetric cells operated at 1.0 mA cm⁻² with 1.0 mAh cm⁻² for 400 cycles. The significant improvement in cycling performance over hundreds of cycles is achieved using LiCoO2 and LiFePO4 cathodes. Furthermore, higher average Coulombic efficiency of 96.4% is realized in a full cell consisting of a high-capacity Ni0.8Co0.1Mn0.1O2 (3.5 mAh cm⁻²) and thin (50 μm) modified Li anodes compared to that of bare Li anodes (94.3%).
Article
In this work, we prepared the nitrogen-doped graphitized porous carbon with embedded nickel-iron alloy nanoparticles ([email protected]) as a sulfur host for lithium-sulfur (Li-S) batteries via a stepwise coating-calcining process of metal-organic framework (MOF) precursors. In the composite, the nitrogen-doped graphitized porous carbon possesses good electronic conductivity and physical adsorption capability for soluble lithium polysulfides (LiPSs). Furthermore, the polar NiFe alloy provides the active sites to anchor the LiPSs and effectively promote the redox conversion kinetics of these intermediates. To confirm this, the density functional theory (DFT) calculations were applied to demonstrate that there is sufficient binding energy between the NiFe alloy and LiPSs. Owing to the above-mentioned benefits, the batteries with the S/[email protected] cathode deliver a high initial reversible capacity (1224 mAh g⁻¹ at 0.2 C) along with a stable cycling ability (565 mAh g⁻¹ at 1 C after 500 cycles). Our findings provide insights towards building the novel sulfur-host materials for advanced Li-S batteries.
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Lithium metal is the ultimate anode candidate for high-energy-density lithium batteries because of its high specific capacity (3860 mAh g ⁻ ¹) and low redox potential (−3.05 V vs. SHE). The nonuniform lithium ions flux and the highly reactive nature of Li metal, however, lead to continuous Li dendrite formation and dead Li growth. In this work, a separator modified by two-dimensional layered MXene (Ti3C2-T, T=-O and -F) and the solid-state electrolyte Li1.3Al0.3Ge1.7(PO4)3 (LAGP) is designed to induce planar Li plating with engineered interphases. The highly mixed conductive nature of LAGP/MXene facilitates the uniform transfer of the lithium ions/electrons. In addition, the -O and -F groups provide more plating sites and lower the Li's initial nucleation energy, which laterally induce planar deposition. The rearrangement of Li atoms inherits the atomic structure of MXene and significantly suppresses the formation of dendritic Li. Furthermore, the in situ formed Ge, Li3PO4 and LiF interphases, originating from the reduction of LAGP, help to stabilize the solid electrolyte interphase (SEI). The LAGP/MXene-modified separator reduces the voltage hypothesis and enables stable Li metal plating and stripping. In a full cell with a high loading of LiCoO2 (20 mg cm⁻²), the engineered separator exhibits stable cycling performance after 200 cycles. The novel strategy of regulating Li deposition and engineering SEIs is facile and efficient and can be applied to other alkali metal anodes.
Article
The uncontrolled dendritic growth, infinite volume propagation and unstable interfacial electrochemistry remain the major bottlenecks to deploy the high-capacity metallic anodes. Further reconciling of the mechanical instable metal electrodeposits upon the geometric deformation in the light-weight, flexible and compactly packed battery model is even more challenging. Here, the Sn4P3 nanocrystallines were anchored within the interconnected reduced graphene oxide film (Sn4P3@rGO) to induce the heterogeneous Na-Sn and Na-P intermediates as the highly sodiophilic “magnets”. Both the galvanostatic cycling and first-principles calculations reveal the apparently reduced nucleation barriers of the Na plating process in the Sn4P3@rGO symmetric cells. Moreover, the device integration of the NaVPO4F cathode and the Sn4P3@rGO substrate with the tailored pre-stored Na (1* excess) realizes 95.6% capacity retention for 150 cycles in a 1.1 mA h full cell. The empirical parameters beyond the prism of the electrode capacity that determine the overall cycle behavior are elucidated, presenting a horizon for architecture designs from both the component level and device level.
Article
The rising demands for efficient regulating the intermittency of renewable energies as well as the rapid spread of portable electronics or electric vehicles have put forward higher requirements on future energy storage systems. Based on the electrochemical reaction difference between lithium and anodes/cathodes, a series of lithium-based energy storage systems, including lithium-ion batteries, lithium-sulfur batteries, lithium-ion capacitors and lithium-oxygen batteries, have been developed and inspired increasing research enthusiasm due to their efficient energy storage features. However, from their current development status, there remains an enormous gap in energy/power density, durability and safety issues between the practical and theoretical performance. Fortunately, 2D nanomaterials, which have been widely applied in lithium-based energy storage systems due to some unique physical/chemical properties, are gradually closing the gap. Therefore, the synthesis approaches for targeting 2D nanomaterials with controlled qualities will be of great significance in this field. On the other hand, for better addressing some stubborn issues during the application, it is necessary to modify 2D nanomaterials by some effective functionalization strategies. In this review, we summarize the general synthesis approaches of 2D nanomaterials as well as functionalization strategies for high-performance lithium-based energy storage systems. Furthermore, the specific role of functionalized 2D nanomaterials in lithium energy storage will be pointed out by presenting the recent achievements in this field. A deep understanding of these works will inspire more ideas for designing 2D nanomaterials with superior performance for advanced electrochemical storage systems, including but not limited to lithium energy storage.
Article
Among current cathode materials, particular attention to Li/Mn-rich layered transition-metal oxides (LMR-NCM) emerged, due to their high energy content accompanied by concurrently low raw material cost. However, until today the step toward a successful market implementation is still impeded by substantial capacity and voltage fade phenomena upon cycling. Herein, we demonstrate a comprehensive structural and morphological approach to increase the long-term stability behavior of LMR-NCM materials within a lithium ion cell. Therefore, a recently introduced core–shell particle design concept was applied, which involves a Co-free and Mn-rich particle core and a low Co-containing shell. The resulting lower anionic redox activity of the shell is key to improve the electrochemical performance. With the aid of a Couette Taylor Flow Reactor, spherical secondary particles with high tap density and narrow particle size distribution are co-precipitated, leading to a valuable hierarchical morphology with superior electrochemical long-term behavior. Thereby, excellent initial Coulombic efficiencies of 90 – 95 % are attained. Finally, another main focus of this work concentrates on the impact of effective performance-improving shell thickness and, thus, provides further insights into the intrinsic nature of the carbonate-derived integrated LMR-NCM active materials.
Article
With the lithium-ion technology approaching its intrinsic limit with graphite-based anodes, Li metal is recently receiving renewed interest from the battery community as potential high capacity anode for next-generation rechargeable batteries. In this focus paper, we review the main advances in this field since the first attempts in the mid-1970s. Strategies for enabling reversible cycling and avoiding dendrite growth are thoroughly discussed, including specific applications in all-solid-state (inorganic and polymeric), Lithium–Sulfur (Li–S) and Lithium-O2 (air) batteries. A particular attention is paid to recent developments of these battery technologies and their current state with respect to the 2030 targets of the EU Integrated Strategic Energy Technology Plan (SET-Plan) Action 7.
Article
LiNi0.5Co0.2Mn0.3O2 (LNCM) cathode surfaces coated with 1–2 wt% Bismaleimide/trithiocyanuric acid (BMI/TCA, BT) oligomer as an additive are successfully prepared for lithium-ion batteries (LIBs). Coin cells comprising the LNCM electrode with 1 wt% BT (1 wt% BT@LNCM) demonstrate similar capacity retention of ca. 91% to the bare LNCM cells at 0.1C for 30 cycles. Electrochemical impedance results confirm that the 1 wt% BT@LNCM cells exhibit identical Li+ diffusion coefficients of ca. 1.1 × 10−10 cm2 s−1 to the bare LNCM cells. TGA/DSC thermal studies show that the delithiated 1 wt% BT@LNCM sample decomposes at a higher temperature than the bare one without electrolyte (ca. 317 vs. 284˚C). In addition, the total heat generation (Qt) of the 1 wt% BT@LNCM electrode with electrolyte is much lower than that of the bare electrode (ca. 599 vs. 824 J g−1). There was strong evidence that the surface coating of BT oligomer on the LNCM could not only reduce the generated heat, but also extended the decomposition temperature. Furthermore, the Qt of the 1 wt% BT@LNCM cells performed at 1C isothermally is reduced by ca. 17% via operando micro-calorimetry; the Qt of the 1 wt% BT@LNCM cells at fully-charged state is also smaller (ca. 3–5%) when the temperature elevates to 300 °C. In summary, LNCM523 cathode materials coated with the 1 wt% BT oligomer show potential for high-energy LIBs application without suffering thermal runaway.
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This paper introduces the first steps towards a general modelling framework for the integrated life cycle engineering (LCE) of future air transportation systems. The focus of analysis lies on the potential environmental implications of batteries powering electric vertical takeoff and landing aircrafts (eVTOLs), which have emerged as an option for urban air mobility to alleviate automobile traffic in cities. The impact of main influencing factors on the sustainability of eVTOLs is discussed, presenting the main modelling requirements for an LCE framework to accompany the transition towards a more sustainable air mobility.
Article
All-solid-state lithium-sulfur batteries (ASSLSBs) hold great promise for safe and high-energy-density energy storage. However, developing high-performance sulfur cathodes has been proven difficult due to low electronic and ionic conductivities and large volume change of sulfur during charge and discharge. Here, we reported an approach to synthesize sulfur cathodes with a mixed electronic and ionic conductivity by infiltrating a solution consisting of Li3PS4 (LPS) solid electrolyte and S active material into a mesoporous carbon (CMK-3). This approach leads to a uniform dispersion of amorphous Li3PS7 (L3PS) catholyte in an electronically conductive carbon matrix, enabling high and balanced electronic/ionic conductivities in the cathode composite. The inherent porous structure of CMK-3 also helps to accommodate the strain/stress generated during the expansion and shrinkage of the active material. In sulfide-based all-solid-state batteries with Li metal as the anode, this cathode composite delivered a high capacity of 1025 mAh g-1 after 50 cycles at 60 oC at 1/8 C. This work highlights the important role of high and balanced electronic and ionic conductivities in developing high-performance sulfur cathodes for ASSLSBs.
Article
Here, we report on the fundamental experimental and computational analyses of target-oriented designed ionic liquid (IL) electrolytes composed of small and (electro)chemically stable borate-based anions with respect to their anion intercalation/de-intercalation behavior in graphite positive electrodes for dual-ion batteries (DIBs). Due to their relatively small size, borate-based anions (e.g., BF4ˉ) and electrolytes are of high interest for DIB cells in order to achieve a high specific capacity, which can, however, be impeded by electrolyte solvation effects. In order to exclude solvent effects, we develop and synthesize novel room-temperature IL electrolytes (RTILs), i.e., Pyr1101BF4/LiBF4 and Pyr1101CF3BF3/LiCF3BF3, which are characterized with respect to stability and anion intercalation behavior. These studies are combined with computational studies to gain fundamental insights into the electronic structures of the BF4ˉ and CF3BF3ˉ acceptor-type graphite intercalation compounds (GICs), staging stoichiometries, theoretical capacities and anion transport properties.
Article
A novel methylated pyrazole derivative, namely 1-methyl-3,5-bis(trifluoromethyl)-1H-pyrazole (MBTFMP) was synthesized for the first time and comprehensively characterized for high voltage application in lithium ion batteries (LIBs). The MBTFMP reactivity and performance was compared to the known 3,5-bis(trifluoromethyl)-1H-pyrazole (BTFMP) functional additive via cyclic voltammetry (CV), constant current cycling as well as post mortem analysis techniques on the graphite and LiNi1/3Mn1/3Co1/3O2 (NMC111) electrodes, such as scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). By means of quantum chemistry (QC) calculations, reductive and oxidative stabilities of MBTFMP and BTFMP functional molecules and their reactivity with the cathode surface were determined. Both reduction and oxidation of BTFMP molecule was coupled with the intermolecular H-transfer that narrowed BTFMP containing electrolyte electrochemical stability window compared to MBTFMP functional additive. The obtained results demonstrate the benefits of hydrogen atom substitution of BTFMP by a methyl-group at the nitrogen atom that resulted in significant improvement of the NMC111||graphite cell cycling performance. This work reveals that with a smart selection of the substitution group and its position in the molecule, functional additives can be tailored in respect of vital physicochemical properties relevant for the high voltage LIB application.
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Protective coating on silicon particles is a strategy reported in literature to improve capacity retention of Si-containing lithium ion batteries. Up to date, the impact of the coating on the cell energy density and specific energy is not considered and guidelines for coating design are missing. In this paper a model is proposed to fill this gap. The model depicts how energy density and specific energy of lithium ion cells based on a Si-graphite composite electrode change in function of coating type, thickness and silicon weight fraction in the negative electrode. Volume changes during lithiation-delithiation and corresponding electrolyte displacement are also considered. Energy density depends on the ratio of coating thickness to silicon particle dimension and weight fraction of silicon in the electrode. Specific energy depends - marginally - also on the coating type. As a case study silicon spherical particles of 200 nm diameter are considered. For a 10 nm coating, the maximum energy density gain vs. state of art graphite negative electrodes is 13%, obtained with 40% weight fraction of silicon in the negative electrode. Above 60 nm thickness no improvement can be obtained vs. state of art graphite negative electrodes.
Article
The big challenge for practical lithium metal batteries is how to make full and reversible utilization of lithium anode. The preformed three-dimensional (3D) porous framework with numerous lithium nucleation sites is able to guide the lithium deposition in the cavity of 3D framework, suppressing the dendrite growth and dimensional change. Herein, we design a nanocapsule structure for lithium metal anodes consisting of 3D graphene with MgxLiy seeds inside. The 3D composite anode not only can be prepared in a simple and scalable process, but also can meet the requirements for both high energy density and long cycle life in the practical cells. During the observation of lithium deposition by transmission electron microscope, it was found that lithium metal was mainly deposited around the MgxLiy seeds within 3D graphene. Thereafter, when the composite anodes are well paired with the commercial LiFePO4 cathodes in coil cells and NCM811 (LiNi0.8Co0.1Mn0.1O2) cathodes in pouch batteries, they are able to deliver the energy density exceeding 350 Wh·kg⁻¹ and long cycle life (>150 cycles) with high energy retention (>85%). The 3D lithium metal/graphene composite anode in the present work provides a promising new avenue for the fabrication of high energy density Li-metal batteries.
Article
Lithium ion battery electrolyte decomposition as a consequence of thermal stress was investigated in Part 1 of a two-part study. The focus of Part 2 is on the influence of the battery cell operation conditions on the electrolyte during cell formation and long-term cycling. Especially, the reactivity of the negative electrode surface and the varied properties of the formed solid electrolyte interphase via vinylene carbonate addition, changing the picture of decomposition products, were addressed. With the help of liquid chromatography hyphenated to high resolution mass spectrometry and fragmentation capabilities, structure elucidation was performed with optimal certainty. This Part 2 confirmed, summarized and extended previous findings to 140 different carbonate, oligo phosphate and mixed phosphate-carbonate species in state-of-the-art electrolytes after moderate cycling conditions and contributes to a targeted investigation of LIB electrolyte aging processes. Furthermore, thermal and electrochemical aging phenomena were discussed and thermal stress marker molecules easing reversed-engineering were postulated.
Article
Lithium-ion batteries (LIBs) and alternative systems, often called post-lithium-ion batteries (PLIBs), appear poised to revolutionize the world's energy infrastructure. Within this paper, we examine LIB and PLIB cathode active materials (CAMs) on metrics of supply risk and environmental impact. We collect data related to each metric through sources including the USGS, European Commission, and LCA databases, transforming them into “risk indicators” with a uniform scale. We then compile these indicators to allow for analysis of each for both technologies and component metals. We examine historic trends and current data, additionally utilizing simulations in order to predict possible future development. We also utilize the CellEst cost model in order to provide analysis of cost and performance alongside supply risk and environmental impact, allowing for a comprehensive view of examined technologies. Several key findings include: cobalt and lithium not only have high supply risk, their supply risk is increasing; nickel, while having a lower supply risk than cobalt, has a higher environmental impact; and PLIB technologies generally have lower supply risk and, at least before cell processing, environmental impact than LIB technologies.
Article
The advancements in lithium ion battery (LIB) research extended its application to the automotive sector. Today, LIBs promise the potential of a greenhouse gas emission-reduced transportation sector to counteract climate change. However, challenging requirements on LIBs regarding fast-charging, energy density, safety and lifetime have to be met for costly battery-powered electric vehicles in order to achieve market implementation. Thus, the study of degradation mechanisms on cell level contributes to the understanding of aging phenomena and will enable improvements for future generations of LIBs. Electrolytes from LIB cells of field-tested electric vehicles of five global original equipment manufacturers were investigated by complementary analytical techniques, giving insights into the feasibility of analysis LIB electrolytes beyond lab-scale. The application of a whole series of established analytical techniques allows to comprehensively analyze LIB electrolytes and to provide reliable conclusions about the LIB cell chemistry. This study interrelates findings through elaboration of the status quo of aged LIB electrolytes after field-tests in terms of degradation and proposed pristine composition (reverse-engineering estimate) of the electrolyte for the first time.
Article
All-solid-state batteries require solid electrolytes that exhibit both high mechanical and chemical stability, as well as a high ionic conductivity. Despite the many decades of research that have led to significant breakthroughs in this field, the synthesis of high-performance ionic conductors is still quite costly with limited scalability, i.e. it is highly energy and time intensive. To this end, the development of cheap and scalable solution-based approaches for fabricating state-of-the-art solid electrolytes is of great interest; however, a deeper understanding over the fundamental solution chemistry and reaction mechanisms governing these synthetic approaches are either absent or are not broadly conveyed in the literature. Herein, we review some of the more recent works on solution-based syntheses of alkali thiophosphates contextualized within a broader scope of the literature in an attempt to provide some additional chemical insights and underline the areas where specific knowledge is lacking. Focusing primarily on Li+ containing electrolytes, we provide a deeper look into both prototypical reagents and possible alternatives, highlight the importance and potential influences of polysulfide / S–S bonding, and discuss the significance of precursor stoichiometry. We hope that this review provides a unique outlook on solution-based syntheses of alkali thiophosphates leading to a better understanding over the critical parameters that govern the optimization of this class of superionic conductors.
Article
While lithium-ion batteries dominate the field of high-energy-density applications, a variety of promising alternative battery technologies exist that might be suitable for various application purposes. Their requirements may vary considerably, e.g., for stationary batteries they are significantly different from those of traction batteries in electric vehicles, i.e., low installation and lifetime cost and a long cycle life are the key parameters for the former ones. Here, we review the recent developments of dual-ion battery (DIB) and particularly of dual-graphite battery technologies, which may be considered as sustainable option for grid storage. We present the progress and challenges of DIB materials and electrolytes, especially with respect to performance parameters, e.g., energy density and cycling stability as well as cost. We discuss the major challenges for practical application and critically evaluate the DIB technology along with an assessment of the potential to fulfill the targets for grid storage.
Article
With the exponential growth of technology in mobile devices and the rapid expansion of electric vehicles into the market, it appears that the energy density of the state-of-the-art Li-ion batteries (LIBs) cannot satisfy the practical requirements. Sulfur has been one of the best cathode material choices due to its high charge storage (1675 mAh g−1), natural abundance and easy accessibility. In this paper, calculations are performed for different cell design parameters such as the active material loading, the amount/thickness of electrolyte, the sulfur utilization, etc. to predict the energy density of Li-S cells based on liquid, polymeric and ceramic electrolytes. It demonstrates that Li-S battery is most likely to be competitive in gravimetric energy density, but not volumetric energy density, with current technology, when comparing with LIBs. Furthermore, the cells with polymer and thin ceramic electrolytes show promising potential in terms of high gravimetric energy density, especially the cells with the polymer electrolyte. This estimation study of Li-S energy density can be used as a good guidance for controlling the key design parameters in order to get desirable energy density at cell-level.
Article
The expansion and shrinkage characteristics of sulfur composite cathode electrode in rechargeable lithium batteries have been investigated. It was found that the sulfur composites electrodes expanded when discharging and shrank when charging again. The thickness change of the electrode was measured to be about 22%. The thickness of lithium metal anodes was also changed when lithium deposition and dissolution, while the sulfur composites electrodes expanded and shrank conversely. The investigation showed that the thickness changes of lithium anode and sulfur composite cathode could be compensated with each other to keep the total thickness of the cell not to change so much.
Article
A high-capacity type of all solid-state battery was developed using sulfur electrode and the thio-LISICON electrolyte. New nano-composite of sulfur and acetylene black (AB) with an average particle size of 1–10nm was fabricated by gas-phase mixing and showed a reversible capacity of 900mAhg−1 at a current density of 0.013mAcm−2.
Article
A synchrotron X-ray powder diffraction pattern was measured for a lithium superionic conductor, Li7P3S11, which has a high conductivity of 3.2×10−3 S cm−1 at room temperature and a low activation energy of 12 kJ mol−1 [Mizuno et al., Solid State Ionics, vol. 177 (2006) 2721]. The crystal structure was solved by a direct space global optimization technique and refined by the Rietveld method. The compound crystallizes in a triclinic cell, space group P-1, a=12.5009(3) Å, b=6.03160(17) Å, c=12.5303(3) Å, α=102.845(3)°, β=113.2024(18)°, γ=74.467(3)°. PS4 tetrahedra and P2S7 ditetrahedra are contained in the structure and Li ions are situated between them.
Article
This report details the Battery Performance and Cost model (BatPaC) developed at Argonne National Laboratory for lithium-ion battery packs used in automotive transportation. The model designs the battery for a specified power, energy, and type of vehicle battery. The cost of the designed battery is then calculated by accounting for every step in the lithium-ion battery manufacturing process. The assumed annual production level directly affects each process step. The total cost to the original equipment manufacturer calculated by the model includes the materials, manufacturing, and warranty costs for a battery produced in the year 2020 (in 2010 US$). At the time this report is written, this calculation is the only publically available model that performs a bottom-up lithium-ion battery design and cost calculation. Both the model and the report have been publically peer-reviewed by battery experts assembled by the U.S. Environmental Protection Agency. This report and accompanying model include changes made in response to the comments received during the peer-review. The purpose of the report is to document the equations and assumptions from which the model has been created. A user of the model will be able to recreate the calculations and perhaps more importantly, understand the driving forces for the results. Instructions for use and an illustration of model results are also presented. Almost every variable in the calculation may be changed by the user to represent a system different from the default values pre-entered into the program. The distinct advantage of using a bottom-up cost and design model is that the entire power-to-energy space may be traversed to examine the correlation between performance and cost. The BatPaC model accounts for the physical limitations of the electrochemical processes within the battery. Thus, unrealistic designs are penalized in energy density and cost, unlike cost models based on linear extrapolations. Additionally, the consequences on cost and energy density from changes in cell capacity, parallel cell groups, and manufacturing capabilities are easily assessed with the model. New proposed materials may also be examined to translate bench-scale values to the design of full-scale battery packs providing realistic energy densities and prices to the original equipment manufacturer. The model will be openly distributed to the public in the year 2011. Currently, the calculations are based in a Microsoft{reg_sign} Office Excel spreadsheet. Instructions are provided for use; however, the format is admittedly not user-friendly. A parallel development effort has created an alternate version based on a graphical user-interface that will be more intuitive to some users. The version that is more user-friendly should allow for wider adoption of the model.
Article
Amorphous oxide and oxynitride lithium electrolyte thin films were synthesized by r.f. magnetron sputtering of lithium silicates and lithium phosphates in Ar, Ar + O2, Ar + N2, or N2. The composition, structure, and electrical properties of the films were characterized using ion and electron beam, X-ray, optical, photoelectron, and a.c. impedance techniques. For the lithium phosphosilicate films, lithium ion conductivities as high as 1.4 × 10−6 S/cm at 25 °C were observed, but none of these films selected for extended testing were stable in contact with lithium. On the other hand, a new thin-film lithium phosphorus oxynitride electrolyte, synthesized by sputtering Li3PO4 in pure N2, was found to have a conductivity of 2 × 10-6 S/cm at 25 °C and excellent long-term stability in contact with lithium. Thin-films cells consisting of a 1 μm thick amorphous V2O5 cathode, a 1 μm thick oxynitride electrolyte film, and a 5 μm thick lithium anode were cycled between 3.7 and 1.5 V using discharge rates of up to 100 μA/cm2 and charge rates of up to 20 μA/cm2. The open-circuit voltage of 3.6 to 3.7 V of fully-charged cells remained virtually unchanged after months of storage.
  • T Placke
  • R Kloepsch
  • S Dühnen
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