Siqi Shi's research while affiliated with Shanghai University and other places

Publications (142)

Article
Currently, lithium fluorinated carbon (Li/CFx) primary batteries have been considered as one of the most promising electrochemical energy supply technologies in the military and medical fields, owing to multiple advantages including high energy density, low self-discharge rate, and good safety. Nevertheless, the intrinsic contradiction between capa...
Article
Full-text available
Redox mediators could catalyse otherwise slow and energy-inefficient cycling of Li–S and Li–O2 batteries by shuttling electrons or holes between the electrode and the solid insulating storage materials. For mediators to work efficiently they need to oxidize the solid with fast kinetics but with the lowest possible overpotential. However, the depend...
Article
Dendrite growth in lithium-ion batteries may bring thermal run-away especially at high current densities, which remains the major bottleneck to implement safe and fast charging for portable electronic devices or electronical vehicles. Designing dendrite inhibition separators with proper pore size is considered to be one of the most promising strate...
Article
Full-text available
Lithium-rich antiperovskites are promising solid-state electrolytes for all-solid-state lithium-ion batteries because of their high structural tolerance and good formability. However, the experimentally reported proton-free Li3OCl is plagued by its inferior interfacial compatibility and harsh synthesis conditions. In contrast, Li2OHCl is a thermody...
Article
Full-text available
Monoclinic natrium superionic conductors (NASICON; Na3Zr2Si2PO12) are well-known Na-ion solid electrolytes which have been studied for 40 years. However, due to the low symmetry of the crystal structure, identifying the migration channels of monoclinic NASICON accurately still remains unsolved. Here, a cross-verified study of Na⁺ diffusion pathways...
Article
Ni-rich Li[NixCoyMn1-x-y]O2 (NCM, x>0.6) is a promising cathode material for lithium-ion batteries while disadvantages like rapid capacity fading and poor rate performance hinder its practical application. In this work, a dual-layer coating is designed and utilized through a solid-gas reaction between the cathode particles and gaseous P2O5, where L...
Article
Full-text available
The electrochemical thermodynamic and kinetic characteristics of rechargeable batteries are critically influenced by the ordering of mobile ions in electrodes or solid electrolytes. However, because of the experimental difficulty of capturing the lighter migration ion coupled with the theoretical limitation of searching for ordered phases in a cons...
Article
Full-text available
Si‐O based materials are promising alloying and conversion‐type anode materials for lithium‐ion batteries and are recently found to be excellent dendrite‐proof layers for lithium‐metal batteries. However, only a small fraction of the Li‐Si‐O compositional space has been reported, significantly impeding the understanding of the phase transition mech...
Article
Full-text available
Replacing the conventional carbonate electrolyte by solid-state electrolyte (SSE) will offer improved safety for lithium-ion batteries. To further improve the energy density, Silicon (Si) is attractive for next generation solid-state battery (SSB) because of its high specific capacity and low cost. High energy density and safe Si-based SSB, however...
Article
Full-text available
Graphene has been used as a conductive substrate to improve the electrochemical performance of layered VS2 as an anode material for lithium-ion batteries. However, there is still a lack of in-depth understanding of the synergistic effect between the layered VS2 and graphene, which contributes to the enhanced performance of Li/Na-ion batteries. In t...
Preprint
Full-text available
Redox mediators could catalyse otherwise slow and energy-inefficient cycling of Li-S and Li-O 2 batteries by shuttling electrons/holes between the electrode and the solid insulating storage materials. For mediators to work efficiently they need to oxidize the solid with fast kinetics yet the lowest possible overpotential. Here, we found that when t...
Article
Identifying descriptors linked to Li⁺ conduction enables rational design of solid state electrolytes (SSEs) for advanced lithium ion batteries, but it is hindered by the diverse and confounding descriptors. To address this, by integrating global and local effects of Li⁺ conduction environment, we develop a generic method of hierarchically encoding...
Article
Full-text available
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 s...
Article
Rational design of solid-state electrolytes (SSEs) with high ionic conductivity and low activation energy (Ea) is vital for all solid-state batteries. Machine learning (ML) techniques have recently been successful in predicting Li⁺ conduction property in SSEs with various descriptors and accelerating the development of SSEs. In this work, we extend...
Article
Lithium-oxygen batteries have a high theoretical capacity, but they are still far from that value in practical applications. In this study, we systematically investigate the synergistic effect of perfluorotributylamine (PFTBA) as an additive in TEGDME-based electrolyte to optimize the electrochemical performance of Li-O2 batteries. PFTBA promotes c...
Article
High-throughput analysis of the ion transport pathways is critical for screening fast ion conductors. Currently, empirical methods, such as the geometric analysis and bond valence site energy (BVSE) methods, are respectively used for the task. Geometric analysis method can only extract geometric and topological pathway properties without considerin...
Article
Full-text available
Rechargeable batteries have a profound impact on our daily life so that it is urgent to capture the physical and chemical fundamentals affecting the operation and lifetime. The phase-field method is a powerful computational approach to describe and predict the evolution of mesoscale microstructures, which can help to understand the dynamic behavior...
Article
Redox mediators are promised to thermodynamically resolve the cathode irreversibility of Li-air battery. However, the sluggish chemical reaction between mediators and discharge products severely restrains fast charging. Here, we combine ab initio calculations and machine learning method to investigate the reaction kinetics between LiOH and I2, and...
Article
Full-text available
Transport characteristics of ionic conductors play a key role in the performance of electrochemical devices such as solid‐state batteries, solid‐oxide fuel cells, and sensors. Despite the significance of the transport characteristics, they have been experimentally measured only for a very small fraction of all inorganic compounds, which limits the...
Article
Rhombohedral NaZr2(PO4)3 is the prototype of all the NASICON‐type materials. The ionic diffusion in these rhombohedral NASICON materials is highly influenced by the ionic migration channels and the bottlenecks in the channels which have been extensively studied. However, no consensus is reached as to which one is the preferential ionic migration ch...
Article
The insufficient ionic conductivity of oxide-based solid electrolyte and the large interfacial resistance between the cathode material and the solid electrolyte severely limit the performances of room-temperature all-solid-state sodium rechargeable batteries. A NASICON solid electrolyte Na3.4Zr1.9Zn0.1Si2.2P0.8O12, with superior room-temperature co...
Article
Full-text available
Designing new cathodes with high capacity and moderate potential is the key to break energy density ceiling imposed by current intercalation chemistry on rechargeable battery. The carbonaceous materials provide high capacities but their low potentials limit their application to anodes. Here, we show that Fermi level tuning by p-type doping can be a...
Article
Development of high-voltage electrolytes with non-flammability is significantly important for future energy storage devices. Aqueous electrolytes are inherently non-flammable, easy to handle, and their electrochemical stability windows (ESWs) can be considerably expanded by increasing electrolyte concentrations. However, further breakthroughs of th...
Article
Machine learning plays an important role in accelerating the discovery and design process for novel electrochemical energy storage materials. This review aims to provide the state-of-the-art and prospects of machine learning for the design of rechargeable battery materials. After illustrating the key concepts of machine learning and basic procedure...
Article
Full-text available
CeO2-based materials have been studied intensively as anodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this work, pristine and europium (Eu)-doped CeO2 nanowires were comprehensively investigated as anode materials for IT-SOFCs, by a combination of theoretical predictions and experimental characterizations. The results demo...
Article
Full-text available
Geometric crystal structure analysis using three-dimensional Voronoi tessellation provides intuitive insights into the ionic transport behavior of metal-ion electrode materials or solid electrolytes by mapping the void space in a framework onto a network. The existing tools typically consider only the local voids by mapping them with Voronoi polyhe...
Article
Full-text available
The combination of a materials database with high-throughput ion-transport calculations is an effective approach to screen for promising solid electrolytes. However, automating the complicated preprocessing involved in currently widely used ion-transport characterization algorithms, such as the first-principles nudged elastic band (FP-NEB) method,...
Article
In anode free batteries (AFBs), the current collector acts as anode simultaneously and has large volume expansion which is generally considered as a negative effect decreasing structural stability of a battery. Moreover, despite many studies on the fast lithium diffusion in the current collector materials of AFB such as copper and aluminum, the inv...
Article
Creep rupture life is a key material parameter for service life and mechanical properties of Ni-based single crystal superalloy materials. Therefore, it is of much practical significance to accurately and efficiently predict creep life. Here, we develop a divide-and-conquer self-adaptive (DCSA) learning method incorporating multiple material descri...
Article
Full-text available
There is a long-standing consciousness that the rhombohedral NASICON-type compounds as promising cathodes for Li+ /Na+ batteries should have inactive M1(6b) sites with ion (de)intercalation occurring only in the M2 (18e) sites. Of particular significance is that M1 sites active for charge/discharge are commonly considered undesirable because the io...
Article
Fast ion conduction in solid-state matrices constitutes the foundation for a wide spectrum of electrochemical systems that use solid electrolytes (SEs), examples of which include solid-state batteries (SSBs), solid oxide fuel cells (SOFCs), and diversified gas sensors. Mixing different solid conductors to form composite solid electrolytes (CSEs) in...
Article
Co3O4 nanoparticles with smaller particle size can expose more active sites to react with electrolyte, thereby exhibiting better supercapacitive performance. However, the size of Co3O4 is difficult to be effectively controlled in traditional carbon matrices. Herein, P, N co-doped carbon matrices with ultra-high surface area and abundant nanocavitie...
Article
The effectiveness of surface coatings in improving the stability and cycling performance of cathodes has been demonstrated since they are first proposed in the 1990's. However, the progress since then is made mostly using the trial-and-error method. Herein, an automated electrochemical-chemical stability design scheme based on first-principles ther...
Article
Full-text available
Cathode degradation is a key factor that limits the cycling stability and rate capability of Li-ion batteries. Coating the surface of cathode particles with metal oxides or fluorides has been reported to suppress this degradation. However, poor Li-ion conductivity of metal oxide and fluoride coatings typically decreases the overall ionic conductivi...
Article
Na super ion conductor (NaSICON), Na1+nZr2SinP3–nO12 is considered one of the most promising solid electrolytes; however, the underlying mechanism governing ion transport is still not fully understood. Here, the existence of a previously unreported Na5 site in monoclinic Na3Zr2Si2PO12 is unveiled. It is revealed that Na+‐ions tend to migrate in a c...
Article
Full-text available
“Water‐in‐salt” (WIS) electrolytes with wide electrochemical stability windows (ESWs) have made a breakthrough in energy density of aqueous batteries and supercapacitors (SCs), but the sluggish ion diffusion limits their widespread application. Although the ion diffusion of WIS electrolytes can be improved by the addition of organic co‐solvents, th...
Article
Full-text available
Gel electrolytes are of great importance for supercapacitors (SCs) operated at high temperatures. However, it is a fundamental challenge for the SCs using aqueous gel electrolytes at elevated temperatures to ensure good work durability due to the evaporation of water. Here we report a “water-in-salt” gel electrolyte that exhibits superior water-ret...
Article
Full-text available
Despite the usage of both experimental and topological methods, realizing a rapid and accurate measurement of the onset temperature (Tg) of GexSe1−x glass transition remains an open challenge. In this paper, a predictive model for the Tg in GexSe1−x glass system is presented by a machine learning method named feature selection based two-stage suppo...
Article
All-solid-state lithium ion batteries are considered to be one of the best candidates for next generation batteries due to the high safety and energy density, but there is still a severe challenge for seeking the high-performance solid electrolytes with high ionic conductivity. Most importantly, the huge resistance at the electrode/electrolyte inte...
Article
Full-text available
Inorganic solid electrolytes have obvious advantages on safety and electrochemical stability compared to organic liquid electrolytes, but the advance on high ionic conductivity of typical electrolytes is still undergoing. Although the first-principles calculation in the ion migration simulation is an important strategy to develop high-performance s...
Article
Expanding the electrochemical stability window (ESW) of aqueous electrolytes is receiving great interest because it directly determines the energy density of electrochemical energy storage devices. Super-concentrated aqueous electrolytes (i.e. “water in salt”, WIS) with extremely high salt-to-water molar ratios enable substantially reduced water ac...
Article
Full-text available
Pseudocapacitance‐induced electrochemical actuators (EC‐actuators) have attracted great attention in robots and artificial intelligence technologies. Despite major efforts to design such EC‐actuators, a molecular‐level understanding of the deformation mechanism is still lacking. Here, a reversible deformation of a freestanding MnO2/Ni bilayer film...
Article
Full-text available
Lithium metal batteries are a promising candidate for future high-energy-density energy storage.
Article
Full-text available
A passivation layer called the solid electrolyte interphase (SEI) is formed on electrode surfaces from decomposition products of electrolytes. The SEI allows Li⁺ transport and blocks electrons in order to prevent further electrolyte decomposition and ensure continued electrochemical reactions. The formation and growth mechanism of the nanometer thi...
Article
The influences of the hole-doped and biaxial strain applied on the electronic structure and magnetism of graphene-like ZnO monolayer are systematically investigated by the first-principles calculations. The results show that hole-doped ZnO monolayer transits from nonmagnetic state to magnetic state once the hole density reaches a certain value (3.6...
Article
Full-text available
The properties of electrolyte are the dominant factors to the overall performance and safety of electrical energy storage devices. The highly concentrated “water in salt” (WIS) electrolytes are inherently non-flammable, moisture-tolerant, and exhibit wide electrochemical stability windows, making them promising electrolytes for high-performance ene...
Article
NiO and graphene composite electrode materials, due to their synergistic effects, are gaining increasing attention in the field of energy storage. However, their nucleation mechanism is uncompletely understood. Herein, we studied the nucleation mechanism of NiO on perfect and defected graphene by density functional theory (DFT). As a result, NiO is...
Article
A metal-free highly torn amine functionalized nitrogen doped graphene (HT-AFNG) used as hydrogen evolution reaction (HER) catalyst is prepared by using a simple synthesis method involving the hydrothermal reaction of graphene oxide in the presence of ammonia and the subsequent ball milling. The metal-free HT-AFNG is efficient for the HER in the aci...
Article
Quantum dots (QDs)/graphene composites are interesting as promising electrode materials for high-performance su-percapacitors due to they can well integrate the complementary features of QDs and graphene. Herein, we demonstrate a MnFe2O4 QDs/nitrogen-doped graphene (NG) material prepared by a controllable solvothermal synthesis, in which ultra-smal...
Article
Lithium borohydride ammoniates can be readily generated by LiBH4 absorbing ammonia at room temperature. Li(NH3)nBH4 (0 < n ≤ 2) performed high ionic conductivity near room temperature, e.g., 2.21 × 10⁻³ S cm⁻¹ for mono-ammoniate at 40°C. A drastic increase in ionic conductivity occurs around 38°C due to the structural change resulting from ammonia...
Article
Vanadium dioxide (VO2) has attracted great attention, with scientific and technological advances over the past few decades due to its reversible metal-insulator transition at 340 K. However, the high phase transition temperature (Tc) of VO2 limits its practical applications. Our first-principles calculations show that VO2(1 1 0) surfaces with adsor...
Article
Two-dimensional (2D) Ti3C2 MXene has attracted great attention in electrochemical energy storage devices (supercapacitors, lithium-ion and sodium-ion batteries) due to its excellent electrical conductivity as well as high volumetric capacity. Nevertheless, existing study showed that multivalent Mg2+ ions cannot reversibly insert into MXene, resulti...
Article
Polyethylene oxide (PEO) based materials are promising candidates for the matrices in composite solid polymer electrolytes (CSPEs) for high-energy density lithium ion batteries. Experimental screening of high-performance CSPEs with high efficiency still appears to be challenging for the moment, due to the complications of the compositions involved....
Article
This neutron-powder-diffraction study unravels that all the hydrogen atoms in (NH4)2Si0.5Ti0.5P4O13 are connected though H bonds, establishing a two-dimensional path between [(Si0.5Ti0.5)P4O13²⁻]n layers for proton diffusion across the crystal structure. Both theoretical and experimental results support an interstitial-proton-conduction mechanism....
Article
Full-text available
Carbon sheets with 3D architectures, large graphitic interlayer spacing, and high electrical conductivity are highly expected to be an ideal anode material for sodium-ion hybrid capacitors (SIHCs). Pursuing a simple synthesis methodology and advancing it from the laboratory to industry is of great importance. In this study, a new approach is presen...