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LiFePO 4 water-soluble binder electrode for Li-ion batteries
Abstract
A new water-soluble elastomer from ZEON Corp. was evaluated as binder with LiFePO4 cathode material in Li-ion batteries. The mechanical characteristic of this cathode was compared to that with PVdF-based cathode binder. The elastomer-based cathode shows high flexibility with good adhesion. The electrochemical performance was also evaluated and compared to PVdF-based cathodes at 25 and at 60°C. A lower irreversible capacity loss was obtained with the elastomer-based cathode, however, aging at 60°C shows a comparable cycle life to that observed with PVdF-based cathodes. The LiFePO4–WSB at high rate shows a good performance with 120mAhg−1 at 10C rate at 60°C.
... Polyvinylidene fluoride (PVDF) has been th choice as an electrode adhesive in commercial lithium-ion batteries due to adhesive strength and electrochemical stability. However, its high cost, reli ardous solvents (e.g., NMP), and negative impacts on operational safety and ment have led research toward alternative materials [89]. Therefore, developing low cost, environmentally friendly, and safer bi come a key pathway to improving the performance and reducing the cost of ies. ...
... Polyvinylidene fluoride (PVDF) has been the traditional choice as an electrode adhesive in commercial lithium-ion batteries due to its excellent adhesive strength and electrochemical stability. However, its high cost, reliance on hazardous solvents (e.g., NMP), and negative impacts on operational safety and the environment have led research toward alternative materials [89]. Therefore, developing low cost, environmentally friendly, and safer binders has become a key pathway to improving the performance and reducing the cost of Li-ion batteries. ...
Lithium iron phosphate (LFP) batteries have emerged as one of the most promising energy storage solutions due to their high safety, long cycle life, and environmental friendliness. In recent years, significant progress has been made in enhancing the performance and expanding the applications of LFP batteries through innovative materials design, electrode engineering, and manufacturing techniques. This review paper provides a comprehensive overview of the recent advances in LFP battery technology, covering key developments in materials synthesis, electrode architectures, electrolytes, cell design, and system integration. This review paper aims to provide a comprehensive overview of the recent advances in lithium iron phosphate (LFP) battery technology, encompassing materials development, electrode engineering, electrolytes, cell design, and applications. By highlighting the latest research findings and technological innovations, this paper seeks to contribute to the continued advancement and widespread adoption of LFP batteries as sustainable and reliable energy storage solutions for various applications. We also discuss the current challenges and future prospects for LFP batteries, emphasizing their potential role in sustainable energy storage solutions for various applications, including electric vehicles, renewable energy integration, and grid-scale energy storage.
... Renowned for its robust covalent bonds and minimal volume alterations during charging and discharging, LFP exhibits remarkable stability, especially when compared to cathode materials with layered structures like NCM. Unlike anode materials such as Si, which undergo substantial volume expansion, LFP typically doesn't necessitate binders with high mechanical strength [143]. However, despite its advantages, LFP grapples with challenges associated with its low electrical conductivity (approximately 10 -9 to 10 -10 S cm -1 ) and Li + ion diffusivity (around 10 -14 to 10 -16 cm 2 s -1 ), factors that can impact its overall performance. ...
... Additionally, while water-soluble polymeric binders have found success with carbonaceous anode materials, their utilization in cathode fabrication remains challenging due to the hygroscopic degradation of cathode active materials. While recent reports indicate success with non-hygroscopic cathode materials such as LFP and spinel-type LiMn2O4 using CMC binders, the hygroscopic nature of Ni-rich cathode materials, such as NCM, poses challenges for water-soluble polymers [143,168]. The high voltage and energy capabilities of Ni-rich cathode materials make them promising for LIBs, but their susceptibility to water-induced degradation complicates the use of water-soluble polymers. ...
The design of binders plays a pivotal role in achieving enduring high power in lithium-ion batteries (LIBs) and extending their overall lifespan. This review underscores the indispensable characteristics that a binder must possess when utilized in LIBs, considering factors such as electrochemical, thermal, and dispersion stability, compatibility with electrolytes, solubility in solvents, mechanical properties, and conductivity. In the case of anode materials, binders with robust mechanical properties and elasticity are imperative to uphold electrode integrity, par-ticularly in materials experiencing substantial volume changes. For cathode materials, the se-lection of a binder hinges on the crystal structure of the cathode material. Other vital consid-erations in binder design encompass cost-effectiveness, adhesion, processability, and envi-ronmental friendliness. Incorporating low-cost, eco-friendly, and biodegradable polymers can contribute significantly to sustainable battery development. This review serves as an invaluable resource for comprehending the prerequisites of binder design in high-performance LIBs and offers insights into binder selection for diverse electrode materials. The findings and principles articulated in this review can be extrapolated to other advanced battery systems, charting a course for the development of next-generation batteries characterized by enhanced perfor-mance and sustainability.
... While improving these properties, the fundamental adhesive property must be preserved and even improved further to withstand volume changes during cyclic battery operations. Traditionally, polyvinylidene di-fluoride (PVDF) has been used widely for fabricating the anode and cathode side of the LIBs due to its high stability, superior adhesive and mechanical abilities, and mechanical support well integrates with the electrodes, and the conductive materials [27][28][29]. ...
... Therefore, the electrodes with PAA, PVP and their combinations as binders are cost effective, compared with those PVDF binders. As previously mentioned, research on PVDF, CMC, PAA and lithiated polyacrylic acid (Li-PAA) as binders of battery electrodes, and PVP as surfactants of printing inks have been widely reported [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. ...
... This leads to simpler and cheaper coater setups, increased safety for workers in the manufacturing plant, and lower energy consumption throughout the process. [3,21,59,60] It is shown that P1 is processable and useable as a water-soluble, fluorine-free alternative to PVDF. Water solubility is also advantageous when recycling electrodes from spent LIBs. ...
The rapidly increasing demand for lithium‐ion batteries and the fight against climate change call for novel materials that enhance performance, enable eco‐friendly processing, and are designed for efficient recycling. In lithium‐ion batteries, the binder polymer, used for cathode production, constitutes an integral but often overlooked component. The currently used polyvinylidene fluoride is processed with toxic organic solvents and has numerous other disadvantages concerning adhesion, conductivity, and recyclability. A change to aqueous processing using new, multi‐functional, purpose‐built materials that are soluble in water and fluorine‐free would thus constitute an important advance in the battery sector. Herein, four water‐soluble surfactant‐like polymers based on 11‐aminoundecanoic acid, that can be obtained in high purity and at a multigram scale are described. Free radical polymerization allows modification of the polymer with a wide variety of comonomers. The materials presented significantly enhance adhesion, are thermally stable at temperatures up to 350 °C, and are compatible with state‐of‐the‐art high‐energy LiNi0.6Mn0.2Co0.2O2 (NMC 622) cathode materials. It is also shown new recycling pathways made possible by the reversible pH‐dependent water‐solubility of the materials.
... The temperature and drying time depend on the amount and type of solvent. Drying can take a long time, even up to 24 h at 120 • C under deep vacuum, and is one of the most expensive steps in the electrode manufacturing process [10,11]. Solvent recovery systems are usually used in commercial manufacturing, due to the high cost of solvents and to prevent pollution of the environment [12]. ...
In this article, an electrode slurry based on activated carbon, which is used to form electrodes of electrochemical capacitors, was assigned to a given group of rheological fluids. The interactions between the textural properties of carbon, the components of the slurry and their impact on the flow nature were explained. Moreover, the viscosity window and optimal ratio between components have been specified, which are necessary to form the right coating on the stainless steel foil as a current collector. The equation that correlates electrode thickness, viscosity, and composition of the slurry (mass of solid materials, solvent, and ratio between components) was obtained by mathematical consideration. Electrochemical measurements were performed to verify the impact of coating quality and thickness on device performance. Finally, the effect of the microstructure formed after slurry preparation and the phenomena accompanying the selected mixing technique are discussed. The paper ends with an economic analysis of electrode slurry production.
... The latter method allows reaching CB mass fractions in water as large as 20%, and the dispersants investigated include polyelectrolytes, 45 ionic surfactants 46,47 such as sulfonate surfactants, [48][49][50][51] sulfonic acids, 52,53 cetyltrimethylammonium bromide (CTAB) 50,54-57 and chloride (CTAC), 58 non-ionic surfactants 50,59 such as silicone surfactants 60 or block copolymers surfactants, 59,61,62 as well as biopolymers such as Arabic gum, 18,63 or polysaccharides. [64][65][66][67] From a structural point of view, dispersants adsorb as monolayers onto the surface of CB particles due to hydrophobic interactions, whose strength depends on the molecular structure and weight of the dispersant. 51,66 Irrespective of the nature of the dispersant, such stabilized CB dispersions behave as shear-thinning fluids. ...
... Nevertheless, the difference from comparatively low sensitivity towards H 2 O has made it preferable choice for the aqueous processed electrodes technologies. Firstly, it was reported by Guerfi and co-workers [48] who studied the function of water-soluble elastomer as binding agent together with CMC as thickener in 1 : 1 proportion. The developed electrodes showed excellent mechanical flexibility and sufficient adhesion toward current collector of aluminum. ...
In this study, we address the most recent innovations in the field of sustainable and environment friendlier binders for electrochemical energy storage devices such as, supercapacitors and batteries accompanied by the explanation, how they could reduce the impacts of environment and cost and enhance the efficiency of the energy equipment. Hitherto, the number of sustainable and environment friendlier binders are categorized according to their chemical composition, processability and natural availability. Different electrochemical devices are being employed to investigate their wide‐ranging advantages. Among them the most commonly employed devices are lithium‐ion batteries (LIBs) and electrochemical double layer supercapacitors (ECDSs). A detailed insight into the anodic half as well as cathodic half has been presented. The Si derived anodes exhibit enhanced capacitive performance as a result of increased cycling ability. This feature owes from the greater interactions between the functionalities and surface of the active particles of the anode material for example, polysaccharides such as carboxymethyl cellulose (CMC)/nanocellulose (NC). On the other hands the transition to water‐processable cathodes is more complicated compared to anodes. Among various polysaccharides, the NC has gained considerable attention as a sustainable and environment friendlier class of greener materials. Herein, we have discussed the role of NC based electrode materials with applications in supercapacitors and batteries. Finally, a comprehensive overview based on the documented work and current views for the further development of NC based aqueous electrodes in the field of electrochemical energy storage devices are discussed.
... The latter method allows reaching CB mass fractions in water as large as 20%, and the dispersants investigated include polyelectrolytes, 43 ionic surfactants 44,45 such as sulfonate surfactants, 46-49 sulfonic acids, 50,51 cetyltrimethylammonium bromide (CTAB) 48,52-54 and chloride (CTAC), 55 non-ionic surfactants 48,56 such as silicone surfactants 57 or block copolymers surfactants, 56,58,59 as well as biopolymers such as Arabic gum, 16,60 or polysaccharides. [61][62][63][64] From a structural point of view, dispersants adsorb as monolayers onto the surface of CB nanoparticles due to hydrophobic interactions, whose strength depends on the molecular structure and weight of the dispersant. 49, 63 Irrespective of the nature of the dispersant, such stabilized CB dispersions behave as shearthinning fluids. ...
Nanocomposites formed by mixing nanoparticles and polymers offer a limitless creative space for the design of functional advanced materials with a broad range of applications in materials and biological sciences. Here we focus on aqueous dispersions of hydrophobic colloidal soot particles, namely carbon black (CB) dispersed with a sodium salt of carboxymethylcellulose (CMC), a food additive known as cellulose gum that bears hydrophobic groups, which are liable to bind physically to CB particles. Varying the relative content of CB nanoparticles and cellulose gum allows us to explore a rich phase diagram that includes a gel phase. We investigate this hydrogel using rheometry and electrochemical impedance spectroscopy. CB-CMC hydrogels display two radically different types of mechanical behaviors that are separated by a critical CMC-to-CB mass ratio . For , i.e., for low CMC concentration, the gel is electrically conductive and shows a glassy-like viscoelastic spectrum, pointing to a microstructure composed of a percolated network of CB nanoparticles decorated by CMC. In contrast, gels with CMC concentration larger than are non-conductive, indicating that the CB nanoparticles are dispersed in the cellulose gum matrix as isolated clusters, and act as physical crosslinkers of the CMC network, hence providing mechanical rigidity to the composite. Moreover, in the concentration range, CB-CMC gels display a power-law viscoelastic spectrum that depends strongly on the CMC concentration. These relaxation spectra can be rescaled onto a master curve that exhibits a power-law scaling in the high-frequency limit, with an exponent that follows Zimm theory, showing that CMC plays a key role in the gel viscoelastic properties for . Our results offer a characterization of CB-CMC dispersions that will be useful for designing nanocomposites based on hydrophobic interactions.
... The aqueous processing of CAMs has been described early for LiFePO 4 (LFP), [1][2][3][4] is still being further investigated [5][6][7] and is also used in the mass-production of such battery cells today. Beyond LFP, a broad range of other cathode materials have been investigated in view of applying water-based processing: From LiCoO 2 8,9 and LiNi x Co y Al 1−x−y O 2 (NCA) [10][11][12][13] to LiNi x Co y Mn 1−x−y O 2 (NCM) using NCM111, [14][15][16][17]18,19 and even NCM811. ...
Water-based processing of positive Li-ion battery electrodes is becoming increasingly important to enable green and sustainable electrode production. Although already widely established for carbon-based anodes, the water-based coating process still poses challenges if applied to cathode materials containing high contents of nickel. Here, positive electrodes using Ni-rich cathode materials with areal capacities of 2.6 mAh/cm ² were prepared either with epoxy, a polyisocyanate-based (ICN) binder, or polyacrylic acid (PAA). All three binders can cross-link with Na-carboxymethyl cellulose used in the formulation. In bi-layer pouch-cells, such cathodes based on epoxy or ICN binders reach an excellent long-term 1 C charge/discharge capacity retention of 85% and 88% after 1000 cycles, whereas electrodes with PAA only reach 65%. Post-mortem analysis of cells after cycling suggests aging of the cathode electrode as the main source of deactivation. Scanning electron microscopy data shows that aqueous processing does not lead to a stronger cracking of the secondary CAM particles and no enhanced dissolution of transition metals was found on the anode side. However, a stronger increase in charge-transfer impedance is observed for the aged water-based cathodes. Thus, the formation of a blocking surface layer appears to be the major reason for performance deterioration with increasing cycle number.
... The binder is crucial for the mechanical stability of the coating during the cell production and has a great influence on the stability during electrochemical cycling where the particulate anode coating is exposed to high mechanical stress through the intercalation process of lithium. [15,16] In addition, due to the ecological and economic advantages of water as a solvent, [17] the new electrode manufacturing process referred to has to be water-based in order to be competitive. Therefore, the use of a mechanically stable thermoplast, such as solid PVDF which needs to be solved in organic solvents, is not suitable. ...
A novel electrode production process, based on a minimal solvent content, is developed for highly viscous water‐based graphite anodes, using a solid mass content of 50% or more compared to conventionally processed anodes. The electrode paste is prepared by mixing the solids with solvent inside of a twin‐screw extruder. Afterward, the extrudate is cut with a strand pelletizer to granules. By inserting the granules into the gap of a two‐roller calender, the current collector foil is coated directly. It is shown that the highly viscous pastes are capable of extended storage stability over several weeks, whereby a temporal and local decoupling of paste preparation and electrode manufacturing can be realized. To enable this innovative electrode processing, a combined development incorporating a selection of new anode binder materials, machinery design, and process parameters has been essential due to strong material‐process interaction, as known in the field of battery electrode production. Because the binder is exposed to greater shear stresses and a short duration time during extrusion mixing, the selection of novel anode binder materials is particularly important. This then needs to be combined with machine design and process parameter optimization, in order to establish this innovative electrode processing method.
... Electrode drying under vacuum can take a wide range of time with some electrodes taking 12-24 h at 120 °C to be completely dry. [251] In commercial applications, an NMP recovery system must be in place during the drying process to recover evaporated NMP due to the high cost and potential environmental pollution. [252,253] On-going efforts to reduce the production cost of Li-ion batteries include the pursuit of positive electrode slurries based on water or removing the need for a solvent altogether. ...
The development of new batteries has historically been achieved through discovery and development cycles based on the intuition of the researcher, followed by experimental trial and error—often helped along by serendipitous breakthroughs. Meanwhile, it is evident that new strategies are needed to master the ever‐growing complexity in the development of battery systems, and to fast‐track the transfer of findings from the laboratory into commercially viable products. This review gives an overview over the future needs and the current state‐of‐the art of five research pillars of the European Large‐Scale Research Initiative BATTERY 2030+, namely 1) Battery Interface Genome in combination with a Materials Acceleration Platform (BIG‐MAP), progress toward the development of 2) self‐healing battery materials, and methods for operando, 3) sensing to monitor battery health. These subjects are complemented by an overview over current and up‐coming strategies to optimize 4) manufacturability of batteries and efforts toward development of a circular battery economy through implementation of 5) recyclability aspects in the design of the battery.
... Then, the PVDF binder with NMP is uniformly mixed with CAMs and acetylene black to form slurry. The final slurry is cast onto the Al foils (cathode current collectors) and dried at 120°C for 12-24 hours to evaporate the NMP solvent [16]. [17]. ...
Lithium-ion battery (LIB)-based electric vehicles (EVs) are regarded as a critical technology for the decarbonization of transportation. The rising demand for EVs has triggered concerns on the supply risks of lithium and some transition metals such as cobalt and nickel needed for cathode manufacturing. There are also concerns about environmental damage from current recycling and disposal practices, as several spent LIBs are reaching the end of their life in the next few decades. Proper LIB end-of-life management can alleviate supply risks of critical materials while minimizing environmental pollution. Direct recycling, which aims at recovering active materials in the cathode and chemically upgrading said materials for new cathode manufacturing, is promising. Compared with pyrometallurgical and hydrometallurgical recycling, direct recycling has closed the material loop in cathode manufacturing via a shorter pathway and attracted attention over the past few years due to its economic and environmental competitiveness. This paper reviews current direct recycling technologies for the cathode, which is considered as the material with the highest economic value in LIBs. We structure this review in line with the direct recycling process sequence: cathode material collection, separation of cathode active materials from other components, and regeneration of degraded cathode active materials. Methods to harvest cathode active materials are well studied. Efforts are required to minimize fluoride emissions during complete separation of cathode active materials from binders and carbon. Regeneration for homogeneous cathode is achieved via solid-state or hydrothermal re-lithiation. However, the challenge of how to process different cathode chemistries together in direct recycling needs to be solved. Overall, the development of direct recycling provides the possibility to accelerate the sustainable recycling of spent LIBs from electric vehicles.
... Novel binder systems that are soluble in water and compatible with cathodes have also attracted increasing attention. For instance, a novel, water-soluble elastomer binder (WSB) [47] was added to carboxymethyl cellulose (CMC) to enhance the flexibility and adhesion of binders in elastomer-based LiFePO 4 cathodes. Improved flexibility was beneficial for enhancing the energy density of electrodes. ...
Polymer binders are critical auxiliary additives to Li-ion batteries that provide adhesion and cohesion for electrodes to maintain conductive networks upon charge/discharge processes. Therefore, polymer binders become interconnected electrode structures affecting electrochemical performances, especially in LiFePO4 cathodes with one-dimensional Li⁺ channels. In this paper, recent improvements in the polymer binders used in the LiFePO4 cathodes of Li-ion batteries are reviewed in terms of structural design, synthetic methods, and working mechanisms. The polymer binders were classified into three types depending on their effects on the performances of LiFePO4 cathodes. The first consisted of PVDF and related composites, and the second relied on waterborne and conductive binders. Profound insights into the ability of binder structures to enhance cathode performance were discovered. Overcoming the bottleneck shortage originating from olivine structure LiFePO4 using efficient polymer structures is discussed. We forecast design principles for the polymer binders used in the high-performance LiFePO4 cathodes of Li-ion batteries. Finally, perspectives on the application of future binder designs for electrodes with poor conductivity are presented to provide possible design directions for chemical structures.
... The binder affects various properties of the cathode, including dispersion and distribution of active materials and CB, electronic and ionic conductivity, porosity, and mechanical properties. Tremendous efforts were put into the development of effective binders, and the most reported materials include PVDF, poly(tetrafluoroethylene) (PTFE), carboxymethyl cellulose (CMC) [319][320][321][322], PEO [ 322 , 323 ], SBR [324] , PAA [ 325 , 326 ], and polyacrylic rubber latex (LA132) and its derivatives [327] . Moreover, blends of two or more binders were employed to further increase the overall performance. ...
Rechargeable batteries that use Li metal as anode are regarded as the most viable alternative to state-of-the-art lithium ion batteries (LIBs), since Li metal batteries (LMBs) are capable of higher-density energy storage. The Nobel Prize in Chemistry 2019 awarded to J. B. Goodenough, S. M. Whittingham, and A. Yoshino for their contributions to the development of LIBs, drew increasing attention to the design of LMBs. Due to the highly reactive nature of metallic lithium and the need to tweak the design of cathode, electrolyte and anode, the industrial success of LMBs has yet to be achieved. In a battery cell, polymeric materials were traditionally used only as separators, cathode binders and packaging materials. In contrast, the enormous progress achieved in a century of polymer chemistry has enabled a large variety of application of polymers in numerous areas of material science. The design and implementation of functional polymers in LMBs is crucial to enhance their practical performance, safety and durability, paving the way to LMB commercialization. This review describes recent advances in the synthesis and tailoring of functional polymer materials to improve the stability of LMBs. The role and application of polymers in different parts of an LMB are presented, including anode, cathode, electrolyte and anode/electrolyte interphases.
... 64 Li et al. demonstrated the feasibility of waterbased manufacturing and recycling with the commercial waterbased binder (CMC) and cathode materials (Fig. 4a). [65][66][67][68] Much effort has been devoted to developing suitable water-soluble binders for different cathode materials. 69,70 However, the impacts of water-soluble binders on the performance of the cathode and the feasibility of water-based manufacturing of different cathode types should be systematically studied. ...
The unprecedented consumption of lithium-ion batteries (LIBs) is underway to meet the needs of modern transportation electrification. Recycling-friendly designs intrinsically facilitate the long-term sustainable utilization of natural resources, reduces the...
... [373] The moderate operation voltages and high chemical stability of LFP, together with low sensitivity to moisture, allow a relatively easy switch from toxic NMP-based PVDF to an aqueous-based natural binder for electrode preparation. This issue was first studied by Zaghib and co-workers [374] using the elastomer-based LFP cathode. The obtained slurry exhibited high flexibility with exceptional adhesion to the current collector and superb electrode performance, with the capacity of 120 mAh g −1 at 10C rate at 60 °C. ...
Materials in nature have evolved to the most efficient forms and have
adapted to various environmental conditions over tens of thousands of years.
Because of their versatile functionalities and environmental friendliness,
numerous attempts have been made to use bio-inspired materials for industrial
applications, establishing the importance of biomimetics. Biomimetics
have become pivotal to the search for technological breakthroughs in the area
of rechargeable secondary batteries. Here, the characteristics of bio-inspired
materials that are useful for secondary batteries as well as their benefits for
application as the main components of batteries (e.g., electrodes, separators,
and binders) are discussed. The use of bio-inspired materials for the synthesis
of nanomaterials with complex structures, low-cost electrode materials
prepared from biomass, and biomolecular organic electrodes for lithium-ion
batteries are also introduced. In addition, nature-derived separators and
binders are discussed, including their effects on enhancing battery performance
and safety. Recent developments toward next-generation secondary
batteries including sodium-ion batteries, zinc-ion batteries, and flexible batteries
are also mentioned to understand the feasibility of using bio-inspired
materials in these new battery systems. Finally, current research trends are
covered and future directions are proposed to provide important insights into
scientific and practical issues in the development of biomimetics technologies
for secondary batteries.
Screen printing is a processing technique that presents significant advantages as it is versatile, low-cost and generates minimal amounts of waste. These features make this technique of interest for use in the production of battery electrodes. However, it is important to understand that changing how the composite electrode is manufactured can impact its microstructure and thus its properties. This study highlights the importance of assessing whether a material presents the appropriate properties to be processed via a specific printing technique (screen printing vs. rod coating) to reach the targeted properties of the composite electrode. More specifically, an evaluation of the printability of water-based composite electrode inks that were formulated with a bio-based polymeric binder (carboxymethyl cellulose) is presented in the context of flat bed screen printing and conventional rod coating. An assessment of the wettability of the ink and its rheological characterization enable the suspension formulation to be adapted to the requirements of each processing technique while ensuring the reproducibility of the suspension formulations for both manufacturing processes. This study demonstrates that screen printing, which allows for significant flexibility and design freedom, can be used to produce composite electrodes as their electrochemical characterization suggests that their performance is similar to that of electrodes prepared using rod coating techniques.
Dry electrode manufacturing methods that do not use NMP can reduce the time and energy required to produce lithium-ion batteries. Polyvinylidene fluoride (PVDF) is a commonly used binder in the dry process. However, there is a lack of research on the effect of dry process parameters on PVDF crystalline types. In our work, the dry process parameters of graphite anode with PVDF as binder are studied, such as the effects of temperature, pressure, and time on the crystallization of PVDF. The effects of powder mixing process and binder content on the performance of dry graphite electrodes are investigated. PVDF processed at 180 °C, 6 MPa, and for 15 min under hot pressing conditions favors the presence of β-crystalline forms. The capacity retention of the prepared electrodes with 10% PVDF loading is superior to that of conventional wet electrodes. Subsequently, reducing PVDF to 5% induces additional cycling stability and rate handling improvements of the dry electrode.
Graphical abstract
Currently, the cells using Lithium Iron Phosphate (LFP) cathode have attracted more attention due to their temperature stability, durability, safety, and fast‐charging capability for lithium‐ion batteries (LIBs). The nano‐sized LFP cathodes have been well‐studied for various applications of LIBs, in particular, electric vehicles and energy storage systems. Herein, we used the open‐pore micron‐sized LFP material as a cathode using an eco‐friendly electrode fabrication process for LIBs. The electrodes have been fabricated using LFP, carbon black, and sodium carboxymethyl cellulose/styrene butadiene rubber binder with various active materials contents (80–85 wt%; LFP80/LFP83/LFP85). These electrodes have been characterized with FTIR, Raman, Peel strength, Swelling, XPS, CV, and EIS analyses. The obtained swelling (18.42%) and peel strength (2.57 N/25 mm) values are on par with the electrodes prepared by the conventional method using a non‐aqueous PVDF binder. The existence of Fe²⁺ in the electrode is confirmed by high‐resolution XPS spectra. From EIS, the obtained solution resistance and charge transfer resistance values of the electrodes are comparable to the standard LFP electrode prepared using PVDF binder. LFP80 exhibited an initial discharge capacity of 130.9 mAh g⁻¹ at 1C‐rate with a capacity retention of > 90% after 300 cycles. The electrode shows excellent rate capability, even at 4C‐rate, it delivered a capacity of 116.3 mAh g⁻¹. In addition, the electrode displayed a stable capacity as high as 148.7 and 75.3 mAh g⁻¹ at 1C‐rate at 65 and −10 °C, respectively. Hence, the LFP80 electrode prepared by eco‐friendly processes can very well be used for versatile LIB applications.
Aqueous binders offer the advantage of greener, less toxic processing of battery electrodes. While such aqueous binders have been successfully utilized in anodes for lithium-ion batteries (LIBs), environmentally sustainable alternatives...
The effects of global warming highlight the urgent need for effective solutions to this problem. The electrification of society, which occurs through the widespread adoption of electric vehicles (EVs), is a critical strategy to combat climate change. Lithium-ion batteries (LIBs) are vital components of the global energy-storage market for EVs, and sodium-ion batteries (SIBs) have gained renewed interest owing to their potential for rapid growth. Improved safety and stability have also put solid-state batteries (SSBs) on the chart of top batteries in the world. This review examines three critical battery technologies: LIBs, SIBs, and SSBs. Although research has historically concentrated on heavier battery components, such as electrodes, to achieve high gravimetric density, binders, which comprise less than 5% of the battery weight, have demonstrated great promise for meeting the increasing need for energy storage. This review thoroughly examines various binders, focusing on their solubilities in water and organic solvents. Understanding binder mechanisms is crucial for developing binders that maintain strong adhesion to electrodes, even during volume fluctuations caused by lithiation and delithiation. Therefore, we investigated the different mechanisms associated with binders. This review also discusses failure mechanisms and innovative design strategies to improve the performance of binders, such as composite, conductive, and self-healing binders. By investigating these fields, we hope to develop energy storage technologies that are more dependable and efficient while also helping to satisfy future energy needs.
Current cathode electrode processing of lithium-ion batteries relies on the conventional use of polyvinylidene fluoride (PVDF) as a binder, accompanied by the toxic solvent N-methylpyrrolidone (NMP). Within cathode materials, the LiNixMn1−x−yCoyO2 (NMC) families stand out as most promising candidates for the next generation of lithium-ion batteries, boasting high energy density and capacity. This review extensively compares traditional battery manufacturing methods with the use of emerging waterborne binders, highlighting the benefits in terms of cost-effectiveness, environmental sustainability, and enhanced processing conditions. The transition to sustainable aqueous processing encounters challenges, including pH elevation, aluminium collector corrosion, and lithium leaching from the NMC materials. The exploration extends to tailored binder selection and additives, crucial in optimizing electrochemical properties for distinct NMC compositions, such as LiNi0.33Mn0.33Co0.33O2 (NMC 111), LiNi0.5Mn0.3Co0.2O2 (NMC 532), LiNi0.6Mn0.2Co0.2O2 (NMC 622) and LiNi0.8Mn0.1Co0.1O2 (NMC 811), and addressing challenges inherent in their aqueous processing. The integration of aqueous binders promises advancements and also shapes a strategic outlook for future research, contributing significantly to the sustainability of lithium-ion batteries.
The current investigation explores the influence of the poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(sodium styrenesulfonate) (PVDF-HFP-g-PSSA) binder on the electrochemical performance of LiFePO4 electrodes using electrochemical measurements of cathodic half-cells. A comparison is made between the electrochemical enhancements of the brush copolymer synthesized by using the atom transfer radical polymerization (ATRP) process and the traditional PVDF binder material. Substituting conventional aluminum current collectors with carbon fiber current collectors effectively enhances the active surface area of the electrodes. The outcomes of the research illustrate that the utilization of the PVDF-HFP-g-PSSA binder leads to reduced concentration polarization and boosted intercalation kinetics, particularly at higher cycle numbers. The cathode comprising the PVDF-HFP-g-PSSA copolymer binder displays a remarkably high initial discharge capacity value of 340 mAh g–1 when subjected to a 0.1 C current density. Additionally, after 300 charge/discharge cycles, a discharge capacity value of 143 mAh g–1 is observed at 0.5 C. Furthermore, the initial capacity at 3 C is 195 mAh g–1 and reaches 160 mAh g–1 after 100 cycles. It is noteworthy that the Coulombic efficiency of this cathode is 100% even after 300 cycles. The synergistic impact of utilizing carbon fibers and sulfonated binders can enhance the potential of structural batteries over conventional lithium-ion batteries (LIBs), enabling them to be used for high-efficiency battery designs suitable for electric vehicles.
The pursuit of industrializing lithium-ion batteries (LIBs) with exceptional energy density and top-tier safety features presents a substantial growth opportunity. The demand for energy storage is steadily rising, driven primarily by the growth in electric vehicles and the need for stationary energy storage systems. However, the manufacturing process of LIBs, which is crucial for these applications, still faces significant challenges in terms of both financial and environmental impacts. Our review paper comprehensively examines the dry battery electrode technology used in LIBs, which implies the use of no solvents to produce dry electrodes or coatings. In contrast, the conventional wet electrode technique includes processes for solvent recovery/drying and the mixing of solvents like N-methyl pyrrolidine (NMP). Methods that use dry films bypass the need for solvent blending and solvent evaporation processes. The advantages of dry processes include a shorter production time, reduced energy consumption, and lower equipment investment. This is because no solvent mixing or drying is required, making the production process much faster and, thus, decreasing the price. This review explores three solvent-free dry film techniques, such as extrusion, binder fibrillation, and dry spraying deposition, applied to LIB electrode coatings. Emphasizing cost-effective large-scale production, the critical methods identified are hot melting, extrusion, and binder fibrillation. This review provides a comprehensive examination of the solvent-free dry-film-making methods, detailing the underlying principles, procedures, and relevant parameters.
The design of binders plays a pivotal role in achieving enduring high power in lithium-ion batteries (LIBs) and extending their overall lifespan. This review underscores the indispensable characteristics that a binder must possess when utilized in LIBs, considering factors such as electrochemical, thermal, and dispersion stability, compatibility with electrolytes, solubility in solvents, mechanical properties, and conductivity. In the case of anode materials, binders with robust mechanical properties and elasticity are imperative to uphold electrode integrity, particularly in materials subjected to substantial volume changes. For cathode materials, the selection of a binder hinges on the crystal structure of the cathode material. Other vital considerations in binder design encompass cost effectiveness, adhesion, processability, and environmental friendliness. Incorporating low-cost, eco-friendly, and biodegradable polymers can significantly contribute to sustainable battery development. This review serves as an invaluable resource for comprehending the prerequisites of binder design in high-performance LIBs and offers insights into binder selection for diverse electrode materials. The findings and principles articulated in this review can be extrapolated to other advanced battery systems, charting a course for developing next-generation batteries characterized by enhanced performance and sustainability.
The increasing demands for sustainable energy storage technologies have prompted extensive research in the development of eco-friendly materials for lithium-ion batteries (LIBs). This research article presents the design of biobased latexes, which are fluorine-free and rely on renewable resources, based on isobornyl methacrylate (IBOMA) and 2-octyl acrylate (2OA) to be used as binders in batteries. Three different compositions of latexes were investigated, varying the ratio of IBOMA and 2OA: (1) Poly2OA homopolymer, (2) Poly(2OA0,6-co-IBOMA0,4) random copolymer, and (3) PolyIBOMA homopolymer. The combination of the two monomers provided a balance between rigidity from the hard monomer (IBOMA) and flexibility from the soft one (2OA). The study evaluated the performance of the biobased latexes using sodium carboxymethyl cellulose (CMC) as a thickener and cobinder by fabricating LiNi0.8Mn0.1Co0.1O2 (NMC 811) cathodes. Also, to compare with the state of the art, organic processed PVDF electrodes were prepared. Among aqueous slurries, rheological analysis showed that the CMC + Poly(2OA0,6-co-IBOMA0,4) binder system resulted in the most stable and well-dispersed slurries. Also, the electrodes prepared with this latex demonstrated enhanced adhesion (210 ± 9 N m–1) and reduced cracks compared to other aqueous compositions. Electrochemical characterization revealed that the aqueous processed cathodes using the CMC + Poly(2OA0,6-co-IBOMA0,4) biobased latex displayed higher specific capacities than the control with no latex at high C-rates (100.3 ± 2.1 vs 64.5 ± 0.8 mAh g–1 at 5C) and increased capacity retention after 90 cycles at 0.5C (84% vs 81% for CMC with no latex). Overall, the findings of this study suggest that biobased latexes, specifically the CMC + Poly(2OA0,6-co-IBOMA0,4) composition, are promising as environmentally friendly binders for NMC 811 cathodes, contributing to the broader goal of achieving sustainable energy storage systems.
To persue sustainable developments, poly (N-vinylformamide) (PNVF) is investigated as a green, bio-derived and water-soluble binder for Li4Ti5O12 (LTO) anode in lithium-ion batteries (LIBs). Electrochemical performance differences between PNVF electrodes and the conventional polyvinylidene fluoride (PVDF) electrodes are presented. The electrodes are characterized by peeling test, the galvanostatic charge/discharge cycle test, electrochemical impedance analysis (EIS), cyclic voltammetry (CV) and scanning electron microscope (SEM). The electrode with 3 wt% PNVF shows higher peeling force than the one with 10 wt% PVDF. The electrodes with 3 wt% PNVF and 10 wt% PVDF exhibit similar rate capability, whereas the capacity retention at 1C-rate is 91.2% (144 mAh/g) and 76.1% (123 mAh/g) after 1000 cycles, respectively. EIS and CV results exhibit that the lithium-titanium oxide (LTO) electrode with optimal PNVF binder (3 wt%) shows lower RSEI and Rct values as compared to that with PVDF counterpart and optimal PNVF electrode exhibits high lithium-ion diffusion coefficient. To enhance the cyclability and high-rate performance, vinylene carbonate (VC) is added as an electrolyte additive afterwards, and the results improve accordingly. Therefore, the results present in this paper demonstrated that PNVF is a potential aqueous binder for LTO anode within green fabrication.
The present work reports a quasi-solid state sodium ion-based asymmetric supercapacitor (ASC) device with nitrogen-doped reduced graphene oxide (NrGO) and boron-doped reduced graphene oxide (BrGO) electrodes. The choice of NrGO (BrGO) for the cathode (anode) is accomplished through a computational investigation of electrode quantum capacitances based on density functional theory (DFT). Nanocellulose is used as an electrode binder due to its biodegradability, enhanced wettability, good ion permeability, and low cost. The NaClO4-PVA based hydrogel membrane is the separator-less quasi-solid state gel electrolyte in the fabricated device. The specific capacitance of the NrGO || BrGO ASC device is obtained as 251.2 F g⁻¹, at a current density of 1 A g⁻¹ with a wide potential window of 2.5 V which is better than the previous reports. This device offers a better performance in comparison to the rGO||rGO, NrGO||NrGO and BrGO||BrGO symmetric supercapacitor (SSC) devices due to the synergistic effect of non-faradic capacitance and pseudocapacitance. The ASC device shows an energy density of 54.5 Wh kg⁻¹ at a power density of 1.25 kW kg⁻¹ and significant capacitance retention of 84.8% after 10,000 cycles at a high current density of 15 A g⁻¹.
P3-Na2/3Ni1/3Mn2/3O2 (P3-NNM) is a promising cathode material for Na-ion batteries, although large volume expansions during cycling mean that challenges around suitable binders still remain. This study reports the use of xanthan gum as a water-soluble, easy to handle, and sustainable biopolymer binder in conjunction with a P3-Na2/3Ni1/3Mn2/3O2-positive electrode material. The conditions for recovering pristine P3-NNM powders, following water-based processing, are established, and the electrochemical performance of cells prepared using the xanthan gum binder are compared to the more traditional polyvinylidene fluoride. Comparable discharge capacities are observed regardless of the binder choice, at ca. 115 mA h g−1 (77 mAh g−1 after 50 cycles; 0.1 C between 2.0 and 4.2 V). The xanthan gum binder cells also show a similar rate capability and slightly higher capacities at faster c-rates vs. polyvinylidene fluoride, making xanthan gum a viable alternative to the traditional organic binders for water-stable cathode materials.
To maintain the integrity of electrodes via conductive binders plays a critical role for Li-ion batteries. In this letter, polyaspartic acid (PASP) was synthesized and used as a novel water-soluble binder for an LiFePO4 (LFP) cathode. At a 1 C current density, this LiFePO4 cathode had a discharge specific capacity of 152 mAh g⁻¹ and retained close to 100% of the initial specific capacity after 40 cycles. Furthermore, this LiFePO4 cathode also maintained a high specific capacity of 122 mAh g⁻¹ at 5C rate. The results of electrochemical impedance spectroscopy and scanning electron microscopy indicated that the layer of PASP that was coated on the LFP electrode, which maintained the integrity of the conductive network and reduced the Li + diffusion path length of the LFP electrode. Based on these properties, PASP could be a prospective binder for LFP cathodes.
L'influence de l'électrolyte dans le phénomène d'emballement thermique des batteries Li-ion a été étudiée à travers le rôle des additifs et du sel de lithium. L'analyse du comportement thermique de l'interface graphite lithié/électrolyte a été effectuée grâce à l'utilisation combinée de la DSC et de techniques analytiques (IR, GC/MS…). Parmi les différents additifs commerciaux "Renforceurs de la SEI" testés (VC, FEC, VEC, 1,3-PS, SA), ceux menant à la formation d'un polymère (VC, FEC) se sont avérés être les plus efficaces tant d'un point de vue de la stabilité thermique du graphite lithié que des performances électrochimiques à 45°C. Une nouvelle famille d'additifs, les dicyanokétènes, a également été étudiée et s'est montrée bénéfique sur la sécurité et la cyclabilité. Le sel LiFSI, introduit dans un électrolyte à base de LiPF6 à hauteur de 33% permet, d'une part, une utilisation jusqu'à 4,2 V et d'autre part, une amélioration du comportement thermique du graphite lithié en présence de VC. Des tests de stabilité thermique de prototypes NMC/graphite de faible capacité (~600 mAh) ont permis de confirmer les effets observés à l'échelle de l'électrode négative. De plus, la forte contribution de l'électrode positive dans le phénomène d'emballement thermique a été mise en évidence ainsi que le rôle clé exercé par la contre pression
Solid-state lithium batteries (SSLBs) are considered to be one of the most promising next-generation Li batteries due to their high capacity and intrinsic safety. However, their sustainable processing is often poorly investigated but could offer additional advantages over conventional batteries in terms of ecological and economic benefits. In this work, a sustainable, water-based processing route for garnet-supported SSLBs featuring a LiFePO4 (LFP)-poly(ethylene oxide) (PEO) composite cathode is presented. Both the LFP-PEO cathode and the thin free-standing garnet separator (105 μm) are fabricated by water-based tapecasting. After optimizing the composition of the cathode, the full
cell with a thin cathode (∼45 μm) delivers a high capacity of 136 mAh g−1 with a high Coulombic efficiency over 99% and good cycling stability for 50 cycles. However, the performance and cycling stability decrease when thicker cathodes (∼110 μm) and higher rates were applied, indicating the need for further optimization. Nevertheless, the here-presented water-based fabrication route provides a baseline for further improvements and pushes SSLB fabrication further toward a green battery production.
Lithium-rich manganese-based cathode materials have the advantages of high specific capacity and operating voltage, but they still pose some problems such as poor cycle performance and serious voltage fading. Here, xanthan gum (XG) with double-helix structure has been investigated as a novel aqueous binder to improve the electrochemical performance of Li[Li0.2Co0.13Ni0.13Mn0.54]O2. When the mass proportion of XG is 5%, the prepared lithium-rich cathode shows the highest specific capacity and best cycle stability. After cycling, the discharge voltage of the lithium-rich cathode decreases by only 273 mV, indicating that XG can effectively inhibit the voltage fading of the lithium-rich material.
The current technologically advancing society requires the development of economically profitable and efficient electrode fabrication routes for lithium ion cells. Binders play an important role in deciding the performance parameters, viz., energy density, rate capability, and cycle life of lithium ion cells. The present review provides a practical guide for the development of aqueous binder based cathodes for lithium ion (Li-ion) cells. In this review, we first discuss the need for aqueous binders in the production of electrodes, particularly for cathodes in Li-ion cells, summarize the challenges in the fabrication of aqueous binder based cathodes, and then highlight the recent developments in aqueous binder based cathodes, targeting to provide a stepping stone for the development of aqueous binder based cathodes with improved sustainability and enhanced electrochemical performance. Aqueous binders for different generations of cathode materials are reviewed in detail with special emphasis given to commercially employed cathode materials.
Recently, water-soluble and aqueous polymers (water-based polymers) have attracted much attention as binders for LIBs because of the need for low-cost materials and environmentally compatible electrode fabrication processes. The water process for the fabrication of cathodes and anodes still has the problems that should be resolved. In this chapter, the origin of the problems, the solutions and the performance of cathodes and anodes that are treated with the processes and techniques is summarized.
Electrodes are the fundamental components in lithium-ion batteries to develop high-performance device systems. The fabrication process of electrodes involves a mixing of active materials, a nonconductive polymeric binder material, and an electrically conductive additive. Binders play a critical role during the electrochemical process, which tightly holds the active materials together within the electrode to provide a long-cycle life. The present study investigates the strength of the interaction for different binders such as vinylidene fluoride (VDF), pyrrole (PY), styrene-butadiene (SB), acrylonitrile (AN), tetrafluoroethylene (TFE), carboxymethylcellulose (CMC), and lignin monomers, coumarylalcohol (LCmA), coniferylalcohol (LCnA), and sinapylalcohol (LSiA), using density functional theory calculations. The result reveals that sustainable binders (CMC, LCmA, LiCnA, and LSiA) exhibit higher interaction energy than unsustainable binders (VDF, PY, SB, AN, and TFE). The highest interaction energy is obtained for the graphene-LiSiA system, followed by graphene-LCnA and graphene-LCmA. Comparing the orientation of the binders on the graphene surface, all binders make a face-to-face arrangement with graphene. This interaction is greatly enhanced for those binders that possess aromatic rings with functional groups (methoxy and hydroxyl). These results provide significant insights for the use of lignocellulosic biomass materials such as lignin and cellulose as binders in energy devices toward more sustainability.
The binder acts a pivotal part in determining the mechanical and electrochemical performances of lithium-ion battery electrodes. Herein, a series of water-soluble Si anode binders based on carboxymethyl chitosan (C-Cs) and styrene-butadiene rubber (SBR) is developed. Water-soluble C-Cs and aqueous emulsion SBR solution are mixed to form C-Cs/SBR binders. The physical properties of the modified Si electrode are investigated through electrolyte swelling test, peeling test, and scanning electron microscopy. The mechanical strength provided to Cu foils and active substances by the C-Cs/SBR binder is higher than that produced by C-Cs. This performance can effectively reduce the stress/strain caused by the drastic volume change of the Si anodes during repeated uses and improve the electrochemical property of lithium-ion batteries. The initial thicknesses of the Si electrodes with polyvinylidene fluoride, C-Cs, and C-Cs/SBR 20 binders are approximately 7.1, 7.2, and 6.9 µm, respectively. After 100 cycles, their initial thicknesses increase to 11.2, 12.4, and 7.2 µm and correspond to expansions of 57.8%, 72.2%, and 4.3%, respectively. The discharge capacity of Si electrodes containing C-Cs/SBR 20 binder reaches to 1340 mAh·g ⁻¹ when the current density is 4 A·g ⁻¹ , and reserves to be 1020 mAh·g ⁻¹ after undergoing 400 cycles of repeated use at 500 mA·g ⁻¹ .
Along with the high energy density and safer battery materials, easy and environment benign electrode processing is also one of the major concerns for the battery manufacturing industries. Therefore, herein, water-based electrode processing is used which reduces manufacturing cost and makes easy and cost-effective recycling of discarded batteries. In addition, the increasing use of Li-ion batteries from portable electronics to electric vehicles has imposed a threat to the environment due to hazardous materials used. The present study also focuses on the replacement of polyvinylidene difluoride (PVDF) non-conducting binder dissolves in toxic solvent N-methyl 2-pyrrolidone with water-soluble poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) conducting binder. The entire study is performed on the synergistic effect of PEDOT: PSS with multi-walled carbon nanotubes (MWCNTs or MC) and carbon black (CB) on Li-ion battery performance using LiFePO4 cathode active material. The discharge capacities were found 144 mAh g⁻¹ and 160 mAh g⁻¹ at 0.1C for composite electrodes LFP/CB-9P and LFP/MC-9P, respectively having 9 wt% PEDOT: PSS. Whereas the composite electrodes LFP/CB-10PV and LFP/MC-10PV having 10 wt% PVDF binder show only capacities 117 mAh g⁻¹ and 134 mAh g⁻¹, respectively. The composite electrode LFP/MC-9P shows the highest capacities up to 20C rate and maximum retention capacity of 84% at 5C after 500 cycles among all samples studied. Whereas electrodes prepared with PVDF binder could not perform well at more than 5C current rate, capacity retention is also found nearly 0% after 500 cycles. Therefore, superior results of PEDOT: PSS and MWCNTs with LiFePO4 propose an environmentally benign composite electrode of next generation Li-ion batteries for electric vehicles.
The demand for portable electronic devices has increased rapidly during past decade, which has driven a concordant growth in battery production. Since their development as a commercial energy storage solution...
Aqueous-based natural graphite particulates for fabrication of lithium-ion battery anodes are investigated with emphasis on chemical control of suspension component interactions among graphite particulates, sodium carboxymethyl cellulose (CMC), and emulsified styrene butadiene rubber (SBR). The chemical stability and dispersion properties of the natural graphite particles are characterized using electroacoustic, flow behaviour and green microstructural observations, as well as by measurement of pore size. Correlation is made between the dispersion characteristics and the electrochemical performance of the particles. The dispersion stability of the graphite suspension is improved by charge development when both SBR and CMC are incorporated into the graphite suspension, compared with an unstable graphite suspension prepared with CMC alone. A method to improve the dispersion and homogeneity of the suspension component based on the use of SBR and CMC is proposed. Electrochemical experiments using a Li–organic electrolyte–as-cast natural graphite half-cell and 750-mAh lithium-ion cells show an initial discharge capacity above 340mAhg−1, improved charge–discharge efficiency, and excellent rate capability.
LiFePO4/gel/natural graphite (NG) cells have been prepared and cycled under a fixed protocol for cycle and calendar life determination. Cell compression of 68kPa was found to represent an optimal balance between cell impedance and the first cycle losses on the individual electrodes with the gel electrolyte. Cells with a Li anode showed capacities of 160 and 78mAh/g LiFePO4 for C/25 and 2C discharge rates, respectively. Rapid capacity and power fade were observed in the LiFePO4/gel/NG cells during cycling and calendar life studies. Diagnostic evaluations point to the consumption of cycleable Li though a side reaction as the reason for performance fade with minimal degradation of the individual electrodes.
We report on lithium intercalation in porous carbon films using a silica‐based gel as binder instead of organic materials such as poly(vinylidene difluoride) and poly(tetrafluoroethylene). Films were fabricated using the sol‐gel method with a series of alkoxy silane precursors. We show that the adhesion, flexibility, and mechanical stability of the carbon films depend on the chemical nature of the precursor. Electrodes prepared using propyltrimethoxy silane as precursor and synthetic graphite particles had a reversible charge capacity of up to , and were stable over multiple cycles. ©1999 The Electrochemical Society
A novel approach to reduce irreversible loss due to carbon anode passivation is described. The graphite particles for use as anode material are pretreated in an aqueous solution of a polyelectrolyte. The polyelectrolyte (gelatin) molecules adsorb onto the particle surface and have a significant impact on anode passivation, as well as on the binding properties of the carbon particles, i.e., gelatin also serves as a particle binder. The reversible capacity of pretreated electrodes is similar to the reversible capacity of conventional electrodes, but the irreversible capacity losses are much smaller and limited to the first charge/discharge cycle. ©2000 The Electrochemical Society
We evaluate poly(acrylamide-co-diallyldimethylammonium chloride) (AMAC) as a water-based binder for the graphite anode of Li-ion batteries. It is shown that AMAC has a similar bonding ability as the conventional poly(vinylidene fluoride) (PVDF) binder, and that the graphite electrodes bonded by AMAC and PVDF have nearly the same cyclability. Advantages of AMAC binder include: (1) it assists in forming a more conductive solid electrolyte interface (SEI) on the surface of graphite and (2) organic liquid electrolyte exhibits better penetration on the AMAC-bonded electrode. Impedance analysis shows that formation of the SEI on the surface of graphite includes two stages. The first stage takes place above 0.15 V and the second stage between 0.15 and 0.04 V. The SEI formed in the first stage is relatively resistive, while that formed in the second stage is highly conductive. For the first stage, the presence of AMAC may enhance the conductivity of the SEI. We performed a storage test on the AMAC-bonded graphite by monitoring the change of open-circuit voltage (OCV) of fully lithiated Li/graphite cells and by comparing their capacity change before and after storage. We observed that OCV of the cell increased gradually, and that capacity loss during the storage recovered in the subsequent lithiation process. Therefore, the OCV increase could be considered a self-delithiation process, which does not consume permanently Li + ions.
In rechargeable lithium ion batteries, carbon materials such as graphite are used as anodes. However, this graphite has limited capacity. The capacity may be improved by controlling the microstructure and surface modification of carbon materials. A high-capacity anode obtained using electrochemically active polyimides as a binder was investigated.
The negative electrode (NE) for lithium‐ion batteries is conventionally made by casting a mixture of various carbon materials
with polyvinylidene difluoride (PVDF) onto copper foil. Differential scanning calorimetry and accelerating rate calorimetry
were used to evaluate the thermal stability of several lithiated NE materials: synthetic graphite (SFG-44), mesocarbon microbeads
(MCMB), lignin‐based hard carbon (HC), and mixtures of these materials. The exothermic heat generation of lithiated NEs, in
the absence of the electrolyte, is attributed to the reaction of PVDF with lithiated carbon
. For all samples here, the total exothermic heat generation increases with an increase in lithiation content. The onset temperature
for the thermal reaction of PVDF with SFG-44 or MCMB does not depend on the lithiation content. However, this onset temperature
decreases as lithiation increases in HC electrodes. These differences are attributed to structural differences between highly
graphitic SFG-44 and MCMB compared with the far less graphitic HC. Total heat generation increases with PVDF binder content.
An alternative resin‐based binder, phenolformaldehyde phenolic‐resin
, is proposed. Full or partial substitution of this material for PVDF lowers the exothermic heat of reaction of the binder
agent with lithiated NE materials. © 2000 The Electrochemical Society. All rights reserved.
The electrochemical behavior of three triphylite (LiFePO 4) ores from different mining localities has been investigated. Two of them show clearly an activity corresponding to the triphylite phase. A discharge capacity of 85 mAh g À1 was obtained. The bene®t of heat treatment that allows to deposit the electronically conductive carbon-based coating on the particles is reported for both natural and synthetic LiFePO 4 samples. Discharge capacity, kinetics and stability upon cycling were all improved after the heating process. The best results were obtained with carbon coatings coming from the decomposition of a modi®ed polycyclic aromatic. In this case, for synthetic samples, the whole capacity was reversibly exchanged and less than 1% of the initial capacity was lost after 10 cycles. # 2001 Elsevier Science B.V. All rights reserved.
Nausea and vomiting are among the most distressing symptoms for cancer patients treated with chemotherapy even with the widespread use of 5-HT3 antagonists. Chemotherapy-induced nausea and vomiting (CINV) is composed of 4 major components: acute nausea, delayed nausea, acute vomiting, and delayed vomiting. Determining the relationship of each component of CINV on the functional status of women undergoing chemotherapy for breast cancer was the purpose of this study. This longitudinal, descriptive study recruited 303 patients with breast cancer undergoing chemotherapy from 40 study sites in the United States. Reliable and valid measures of CINV and functional status were employed. Patients demonstrated significant decreases in the following aspects of functional status as measured by the SF-36: physical functioning (P < .0005), role limitations due to physical problems (P = .003), general health (P = .029), vitality (P < .0005), and social functioning (P = .001). The pattern of reduction in usual activities and increase in hours of resting correlated best with 2 components of CINV--delayed nausea and delayed vomiting (P < .0001, each). The results of this study suggest that control of delayed CINV may contribute to the functional improvement of women receiving chemotherapy for breast cancer.