Application of deep learning for informatics aided design of electrode materials in metal-ion batteries

To develop emerging electrode materials and improve the performances of batteries,the machine learning techniques can provide insights to discover,design and develop battery new materials in high-throughput way.In this paper,two deep learning models are developed and trained with two feature groups extracted from the Materials Project datasets to predict the battery electrochemical performances including average voltage,specific capacity and specific energy.The deep learning models are trained with the multilayer perceptron as the core.The Bayesian optimization and Monte Carlo methods are applied to improve the prediction accuracy of models.Based on 10 types of ion batteries,the correlation coefficients are maintained above 0.9 compared to DFT calculation results and the mean absolute error of the prediction results for voltages of two models can reach 0.41 V and 0.20 V,respectively.The electrochemical performance prediction times for the two trained models on thousands of batteries are only 72.9 ms and 75.7 ms.Besides,the two deep learning models are applied to approach the screening of emerging electrode materials for sodium-ion and potassium-ion batteries.This work can contribute to a high-throughput computational method to accelerate the rational and fast materials discovery and design.

The design and engineering strategies of metal tellurides for advanced metal-ion batteries

Owning various crystal structures and high theoretical capacity,metal tellurides are emerging as promising electrode materials for high-performance metal-ion batteries(MBs).Since metal telluride-based MBs are quite new,fundamental issues raise regarding the energy storage mechanism and other aspects affecting electrochemical performance.Severe volume expansion,low intrinsic conductivity and slow ion diffusion kinetics jeopardize the performance of metal tellurides,so that rational design and engineering are crucial to circumvent these disadvantages.Herein,this review provides an in-depth discussion of recent investigations and progresses of metal tellurides,beginning with a critical discussion on the energy storage mechanisms of metal tellurides in various MBs.In the following,recent design and engineering strategies of metal tellurides,including morphology engineering,compositing,defect engineering and heterostructure construction,for high-performance MBs are summarized.The primary focus is to present a comprehensive understanding of the structural evolution based on the mechanism and corresponding effects of dimension control,composition,electron configuration and structural complexity on the electrochemical performance.In closing,outlooks and prospects for future development of metal tellurides are proposed.This work also highlights the promising directions of design and engineering strategies of metal tellurides with high performance and low cost.

Emerging two-dimensional Mo-based materials for rechargeable metal-ion batteries:Advances and perspectives

With the rapid development of rechargeable metal-ion batteries(MIBs)with safety,stability and high energy density,significant efforts have been devoted to exploring high-performance electrode materials.In recent years,two-dimensional(2D)molybdenum-based(Mo-based)materials have drawn considerable attention due to their exceptional characteristics,including low cost,unique crystal structure,high theoretical capacity and controllable chemical compositions.However,like other transition metal compounds,Mo-based materials are facing thorny challenges to overcome,such as slow electron/ion transfer kinetics and substantial volume changes during the charge and discharge processes.In this review,we summarize the recent progress in developing emerging 2D Mo-based electrode materials for MIBs,encompassing oxides,sulfides,selenides,carbides.After introducing the crystal structure and common synthesis methods,this review sheds light on the charge storage mechanism of several 2D Mo-based materials by various advanced characterization techniques.The latest achievements in utilizing 2D Mo-based materials as electrode materials for various MIBs(including lithium-ion batteries(LIBs),sodium-ion batteries(SIBs)and zinc-ion batteries(ZIBs))are discussed in detail.Afterwards,the modulation strategies for enhancing the electrochemical performance of 2D Mo-based materials are highlighted,focusing on heteroatom doping,vacancies creation,composite coupling engineering and nanostructure design.Finally,we present the existing challenges and future research directions for 2D Mo-based materials to realize high-performance energy storage systems.

Design strategies for rechargeable aqueous metal-ion batteries

Rechargeable aqueous metal-ion batteries(AMBs)have attracted extensive scientific and commercial interest due to their potential for cost-effective,highly safe,and scalable stationary energy storage.However,their limited output voltage,inadequate energy density,and poor reversibility of ambiguous electrode reactions in aqueous electrolytes strongly limit their practical viability.This review aims to elucidate the challenges of existing AMBs from the material design to whole device applications.We summarize the emerging electrochemistry,fundamental properties,and key issues in interfacial behaviors of various classes of prevailing AMBs,including aqueous alkali metal-ion batteries and multivalent-ion batteries,and present an appraisal of recent advances for addressing the performance deficiency.Specifically,the progress of zinc-ion batteries is highlighted to provide a ubiquitous guideline for their commercialization in the grid-scale energy storage.Finally,we figure out the dominating general challenges for achieving high-performance AMBs,laying out a perspective for future breakthroughs.

Two-dimensional organic cathode materials for alkali-metal-ion batteries

With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional（2D） organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery（LIB）, lithium sulfur battery（LSB）, lithium air battery（LAB） and sodium ion battery（SIB） are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.

Electrode materials for aqueous multivalent metal-ion batteries: Current status and future prospect

In recent years,the pursuit of high-efficiency electrochemical storage technology,the multivalent metalion batteries (MIBs) based on aqueous electrolytes have been widely explored by researchers because of their safety,environmental friendliness,abundant reserves and low price,and especially the merits in energy and power densities.This review firstly expounds on the problems existing in the electrode materials of aqueous multivalent MIBs (Zn^(2+),Mg^(2+),Al^(3+),Ca^(2+)),from the classical inorganic materials to the emerging organic compounds,and then summarizes the design strategies in bulk and interface structure of electrodes with favorable kinetics and stable cycling performance,especially laying the emphasis on the charge storage mechanism of cathode materials and dendrite-free Zinc anode from the aspect of electrolyte optimization strategies,which can be extended to other aqueous multivalent MIBs.Ultimately,the possible development directions of the aqueous multivalent MIBs in the future are provided,anticipating to provide a meaningful guideline for researchers in this area.

Emerging Carbonyl Polymers as Sustainable Electrode Materials for Lithium-Free Metal-Ion Batteries

Lithium-ion batteries using inorganic electrode materials have been long demonstrated as the most promising power supplies for portable electronics,electric vehicles,and smart grids.However,the increasing cost and descending availability of lithium resources in combination with the limited electrochemical performance and eco-sustainability have created serious concerns with the competitiveness of lithium-ion batteries.There is a pressing need for the discovery of new redox chemistries between the alternative host materials and charge carriers.Organic nonlithium batteries using organic electrodes have recently attracted considerable interests as the future substitutes for energy storage systems,because of their combined merits(e.g.,natural abundance,rich chemistry of organics,rapid kinetics,and multielectron redox)of Li-free batteries and organic electrodes.Herein,an overview on the state-of-the-art developments of emerging carbonyl polymers for nonlithium metal-ion batteries is comprehensively presented with a primary focus on polyquinones and polyimides from the perspective of chain engineering.Six distinct categories,including monovalent(Na^(+),K^(+)) and multivalent(Mg^(2+),Zn^(2+),Ca^(2+),Al^(3+)) metal-ions batteries are individually outlined.Advantages of polymer electrode materials and characteristics of charge storage mechanisms are highlighted.Some key performance parameters such as specific capacity,rate capability,and cycle stability are carefully discussed.Moreover,aqueous nonlithium batteries based on carbonyl polymers are specially scrutinized due to the less reactivity of Li-free metals when exposed in aqueous electrolytes and ambient atmosphere.Current challenges and future prospects of developing polymer-based batteries are proposed finally.This review provides a fundamental guidance for the future advancement of next-generation sustainable batteries beyond lithium-ion batteries.

Multiple transition metals modulated hierarchical networks for high performance of metal-ion batteries

Searching anodes with excellent electrochemical performance has been in great demand for rechargeable metal ion batteries. In this contribution, Fe/Co co-doped Ni S with N-based carbon(Fe Co-NiS@NC) derived from trimetallic Prussian blue analogue is designed and synthesized. The composition can be easily adjusted and modulated by multi-metals. In addition, the well-designed carbon nanocubes effectively promote electronic conductivity and buffer the volume change upon charge and discharge cycling, resulting in good capacity and long-term cycle life for both lithium-ion batteries and sodium-ion batteries, with capacities of 1018 m Ah g^(-1)(vs. Li/Li^(+)) and 454 m Ah g^(-1)(vs. Na/Na^(+)), respectively, after 100 cycles.Kinetics studies indicate that the electrochemical behaviors are manipulated by both diffusion and pseudocapacitance processes. These strategies would open new opportunities and potention for novel energy storage.

Recent progress in COF-based electrode materials for rechargeable metal-ion batteries

Covalent organic frameworks(COFs)have emerged as promising electrode materials for rechargeable metal-ion batteries and have gained much attention in recent years due to their high specific surface area,inherent porosity,tunable molecular structure,robust framework,abundant active sites.Moreover,compared with inorganic materials and small organic molecules,COFs have the advantages of multi-electron transfer,short pathways,high cycling stability.Although great progress on COF-based electrodes has been made,the corresponding electrochemical performance is still far from satisfactory for practical applications.In this review,we first summarize the fundamental background of COFs,including the species of COFs(different active covalent bonds)and typical synthesis methods of COFs.Then,the key challenges and the latest research progress of COF-based cathodes and anodes for metal-ion batteries are reviewed,including Li-ion batteries,Na-ion batteries,K-ion batteries,Zn-ion batteries,et al.Moreover,the effective strategies to enhance electrochemical performance of COF-based electrodes are presented.Finally,this review also covers the typical superiorities of COFs used in energy devices,as well as providing some perspectives and outlooks in this field.We hope this review can provide fundamental guidance for the development of COFbased electrodes for metal-ion batteries in the further research.

Covalent organic frameworks as electrode materials for rechargeable metal-ion batteries

Covalent organic frameworks(COFs),as a class of crystalline porous polymers,featuring designable structures,tunable frameworks,well-defined channels,and tailorable functionalities,have emerged as promising organic electrode materials for rechargeable metal-ion batteries in recent years.Tremendous efforts have been devoted to improving the electrochemical performance of COFs.However,although significant achievements have been made,the electrochemical behaviors of developed COFs are far away from the desirable performance for practical batteries owing to intrinsic problems,such as poor electronic conductivity,the trade-off relationship between capacity and redox potential,and unfavorable micromorphology.In this review,the recent progress in the development of COFs for rechargeable metal-ion batteries is presented,including Li,Na,K,and Zn ion batteries.Various research strategies for improving the electrochemical performance of COFs are summarized in terms of the molecular-level design and the material-level modification.Finally,the major challenges and perspectives of COFs are also discussed in the aspect of large-scale production and electrochemical performance improvements.

Recent Advances in Covalent Organic Framework Electrode Materials for Alkali Metal-Ion Batteries

Owing to the shortcomings of traditional electrode materials in alkalimetal-ion batteries(AIBs),such as limited reversible specific capacity,low power density,and poor cycling performance,it is particularly important to develop new electrode materials.Covalent organic frameworks(COFs)are crystalline porous polymers that incorporate organic building blocks into their periodic structures through dynamic covalent bonds.COFs are superior to organic materials because of their high designability,regular channels,and stable topology.Since the first report of D_(TP)-A_(NDI)-COF as a cathode material for lithium-ion batteries in 2015,research on COF electrode materials has made continuous progress and breakthroughs.This review briefly introduces the characteristics and current challenges associated with COF electrode materials.Furthermore,we summarize the basic reaction types and active sites according to the categories of covalent bonds,including B–O,C=N,C–N,and C=C.Finally,we emphasize the perspectives on basic structure and morphology design,dimension and size design,and conductivity improvement of COFs based on the latest progress in AIBs.We believe that this review provides important guidelines for the development of high-efficiency COF electrode materials and devices for AIBs.

Carbon materials for metal-ion batteries

Metal-ion(Li-,Na-,Zn-,K-,Mg-,and Al-ion)batteries(MIBs)play an important role in realizing the goals of“emission peak and carbon neutralization”because of their green production techniques,lower pollution,high voltage,and large energy density.Carbon-based materials are indispensable for developing MIBs and are widely adopted as active or auxiliary materials in the anodes and cathodes.For example,carbon-based materials,includ-ing graphite,Si/C and hard carbon,have been used as anode materials for Li-and Na-ion batteries.Carbon can also be used as a conductive coating for cathodes,such as in LiFePO 4/C,to achieve better performance.In addition,as new high-valence MIBs(Zn-,Al-,and Mg-ion)have emerged,a growing number of novel carbon-based mate-rials have been utilized to construct high-performance MIBs.Herein,we discuss the recent development trends in advanced carbon-based materials for MIBs.The impact of the structure properties of advanced carbon-based materials on energy storage is addressed,and a perspective on their development is also proposed.

Mechanism of internal thermal runaway propagation in blade batteries

Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe use.This study experimentally investigated the mechanism underlying thermal runaway propagation within a blade battery by using a nail to trigger thermal runaway and thermocouples to track its propagation inside a cell.The results showed that the internal thermal runaway could propagate for up to 272 s,which is comparable to that of a traditional battery module.The velocity of the thermal runaway propagation fluctuated between 1 and 8 mm s^(-1),depending on both the electrolyte content and high-temperature gas diffusion.In the early stages of thermal runaway,the electrolyte participated in the reaction,which intensified the thermal runaway and accelerated its propagation.As the battery temperature increased,the electrolyte evaporated,which attenuated the acceleration effect.Gas diffusion affected thermal runaway propagation through both heat transfer and mass transfer.The experimental results indicated that gas diffusion accelerated the velocity of thermal runaway propagation by 36.84%.We used a 1D mathematical model and confirmed that convective heat transfer induced by gas diffusion increased the velocity of thermal runaway propagation by 5.46%-17.06%.Finally,the temperature rate curve was analyzed,and a three-stage mechanism for internal thermal runaway propagation was proposed.In Stage I,convective heat transfer from electrolyte evaporation locally increased the temperature to 100℃.In Stage II,solid heat transfer locally increases the temperature to trigger thermal runaway.In StageⅢ,thermal runaway sharply increases the local temperature.The proposed mechanism sheds light on the internal thermal runaway propagation of blade batteries and offers valuable insights into safety considerations for future design.

Engineering Strategies for Suppressing the Shuttle Effect in Lithium–Sulfur Batteries

Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of Li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in Li–S batteries.

Progress,challenges,and prospects of spent lithium-ion batteries recycling:A review

The recycling and reutilization of spent lithium-ion batteries(LIBs)have become an important measure to alleviate problems like resource scarcity and environmental pollution.Although some progress has been made,battery recycling technology still faces challenges in terms of efficiency,effectiveness and environmental sustainability.This review aims to systematically review and analyze the current status of spent LIB recycling,and conduct a detailed comparison and evaluation of different recycling processes.In addition,this review introduces emerging recycling techniques,including deep eutectic solvents,molten salt roasting,and direct regeneration,with the intent of enhancing recycling efficiency and diminishing environmental repercussions.Furthermore,to increase the added value of recycled materials,this review proposes the concept of upgrading recycled materials into high value-added functional materials,such as catalysts,adsorbents,and graphene.Through life cycle assessment,the paper also explores the economic and environmental impacts of current battery recycling and highlights the importance that future recycling technologies should achieve a balance between recycling efficiency,economics and environmental benefits.Finally,this review outlines the opportunities and challenges of recycling key materials for next-generation batteries,and proposes relevant policy recommendations to promote the green and sustainable development of batteries,circular economy,and ecological civilization.

Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion Batteries

Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

Model reduction of fractional impedance spectra for time–frequency analysis of batteries, fuel cells, and supercapacitors

Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.

Highly Efficient Aligned Ion‑Conducting Network and Interface Chemistries for Depolarized All‑Solid‑State Lithium Metal Batteries

Improving the long-term cycling stability and energy density of all-solid-state lithium(Li)-metal batteries(ASSLMBs)at room temperature is a severe challenge because of the notorious solid–solid interfacial contact loss and sluggish ion transport.Solid electrolytes are generally studied as two-dimensional(2D)structures with planar interfaces,showing limited interfacial contact and further resulting in unstable Li/electrolyte and cathode/electrolyte interfaces.Herein,three-dimensional(3D)architecturally designed composite solid electrolytes are developed with independently controlled structural factors using 3D printing processing and post-curing treatment.Multiple-type electrolyte films with vertical-aligned micro-pillar(p-3DSE)and spiral(s-3DSE)structures are rationally designed and developed,which can be employed for both Li metal anode and cathode in terms of accelerating the Li+transport within electrodes and reinforcing the interfacial adhesion.The printed p-3DSE delivers robust long-term cycle life of up to 2600 cycles and a high critical current density of 1.92 mA cm^(−2).The optimized electrolyte structure could lead to ASSLMBs with a superior full-cell areal capacity of 2.75 mAh cm^(−2)(LFP)and 3.92 mAh cm^(−2)(NCM811).This unique design provides enhancements for both anode and cathode electrodes,thereby alleviating interfacial degradation induced by dendrite growth and contact loss.The approach in this study opens a new design strategy for advanced composite solid polymer electrolytes in ASSLMBs operating under high rates/capacities and room temperature.

The initial stages of Li_(2)O_(2) formation during oxygen reduction reaction in Li-O_(2) batteries:The significance of Li_(2)O_(2) in charge-transfer reactions within devices

Lithium-oxygen batteries are a promising technology because they can greatly surpass the energy density of lithium-ion batteries.However,this theoretical characteristic has not yet been converted into a real device with high cyclability.Problems with air contamination,metallic lithium reactivity,and complex discharge and charge reactions are the main issues for this technology.A fast and reversible oxygen reduction reaction(ORR)is crucial for good performance of secondary batteries',but the partial knowledge of its mechanisms,especially when devices are concerned,hinders further development.From this perspective,the present work uses operando Raman experiments and electrochemical impedance spectroscopy(EIS)to assess the first stages of the discharge processes in porous carbon electrodes,following their changes cycle by cycle at initial operation.A growth kinetic formation of the discharge product signal(Li_(2)O_(2))was observed with operando Raman,indicating a first-order reaction and enabling an analysis by a microkinetic model.The solution mechanism in the evaluated system was ascribed for an equivalent circuit with three time constants.While the time constant for the anode interface reveals to remain relatively constant after the first discharge,its surface seemed to be more non-uniform.The model indicated that the reaction occurs at the Li_(2)O_(2) surface,decreasing the associated resistance during the initial discharge phase.Furthermore,the growth of Li_(2)O_(2) forms a hetero-phase between Li_(2)O_(2)/electrolyte,while creating a more compact and homogeneous on the Li_(2)O_(2)/cathode surface.The methodology here described thus offers a way of directly probing changes in surface chemistry evolution during cycling from a device through EIS analysis.

Characterization and identification towards dynamic-based electrical modeling of lithium-ion batteries

Lithium-ion batteries are widely recognized as a crucial enabling technology for the advancement of electric vehicles and energy storage systems in the grid.The design of battery state estimation and control algorithms in battery management systems is usually based on battery models,which interpret crucial battery dynamics through the utilization of mathematical functions.Therefore,the investigation of battery dynamics with the purpose of battery system identification has garnered considerable attention in the realm of battery research.Characterization methods in terms of linear and nonlinear response of lithium-ion batteries have emerged as a prominent area of study in this field.This review has undertaken an analysis and discussion of characterization methods,with a particular focus on the motivation of battery system identification.Specifically,this work encompasses the incorporation of frequency domain nonlinear characterization methods and dynamics-based battery electrical models.The aim of this study is to establish a connection between the characterization and identification of battery systems for researchers and engineers specialized in the field of batteries,with the intention of promoting the advancement of efficient battery technology for real-world applications.