All-solid-state lithium batteries(ASSLBs)have attracted increasing attention due to their high safety and energy density.Among all corresponding solid electrolytes,sulfide electrolytes are considered to be the most pr...All-solid-state lithium batteries(ASSLBs)have attracted increasing attention due to their high safety and energy density.Among all corresponding solid electrolytes,sulfide electrolytes are considered to be the most promising ion conductors due to high ionic conductivities.Despite this,many challenges remain in the application of ASSLBs,including the stability of sulfide electrolytes,complex interfacial issues between sulfide electrolytes and oxide electrodes as well as unstable anodic interfaces.Although oxide cathodes remain the most viable electrode materials due to high stability and industrialization degrees,the matching of sulfide electrolytes with oxide cathodes is challenging for commercial use in ASSLBs.Based on this,this review will present an overview of emerging ASSLBs based on sulfide electrolytes and oxide cathodes and high-light critical properties such as compatible electrolyte/electrode interfaces.And by considering the current challenges and opportunities of sulfide electrolyte-based ASSLBs,possible research directions and perspectives are discussed.展开更多
Sodium-ion batteries have the potential to be an alternative to lithium-ion batteries especially for applications such as large-scale grid energy storage. The development of suitable cathode materials is crucial to th...Sodium-ion batteries have the potential to be an alternative to lithium-ion batteries especially for applications such as large-scale grid energy storage. The development of suitable cathode materials is crucial to the commercialization of sodium-ion batteries.Sodium-based layered-type transition metal oxides are promising candidates as cathode materials as they offer decent energy density and are easy to be synthesized. Unfortunately, most layered oxides suffer from poor air-stability, which greatly increases the cost of manufacturing and handling. The air-sensitivity severely limits the development and commercial application of sodium-ion batteries. A review that summarizes the latest understanding and solutions of air-sensitivity is desired. In this review,the background and fundamentals of sodium-based layered-type cathode materials are presented, followed by a discussion on the latest research on air-sensitivity of these materials. The mechanism is complex and involves multiple chemical and physical reactions. Various strategies are shown to alleviate some of the corresponding problems and promote the feasible application of sodium-ion batteries, followed by an outlook on current and future research directions of air-stable cathode materials. It is believed that this review will provide insights for researchers to develop practically relevant materials for sodium-ion batteries.展开更多
Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides...Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides distinguish themselves from the mains cathode materials of SIBs owing to their advantages such as high specific capacity,simple synthesis route,and environmental benignity.However,the commercial development of the layered oxides is limited by sluggish kinetics,complex phase transition and poor air stability.Based on the research ideas from macro-to micro-scale,this review systematically summarizes the current optimization strategies of sodium-ion layered oxide cathodes(SLOC)from different dimensions:microstructure design,local chemistry regulation and structural unit construction.In the dimension of microstructure design,the various structures such as the microspheres,nanoplates,nanowires and exposed active facets are prepared to improve the slow kinetics and electrochemical performance.Besides,from the view of local chemistry regulation by chemical element substitution,the intrinsic electron/ion properties of SLOC have been enhanced to strengthen the structural stability.Furthermore,the optimization idea of endeavors to regulate the physical and chemical properties of cathode materials essentially is put forward from the dimension of structural unit construction.The opinions and strategies proposed in this review will provide some inspirations for the design of new SLOC in the future.展开更多
Sodium-ion batteries(SIBs)are considered as a low-cost complementary or alternative system to prestigious lithium-ion batteries(LIBs)because of their similar working principle to LIBs,cost-effectiveness,and sustainabl...Sodium-ion batteries(SIBs)are considered as a low-cost complementary or alternative system to prestigious lithium-ion batteries(LIBs)because of their similar working principle to LIBs,cost-effectiveness,and sustainable availability of sodium resources,especially in large-scale energy storage systems(EESs).Among various cathode candidates for SIBs,Na-based layered transition metal oxides have received extensive attention for their relatively large specific capacity,high operating potential,facile synthesis,and environmental benignity.However,there are a series of fatal issues in terms of poor air stability,unstable cathode/electrolyte interphase,and irreversible phase transition that lead to unsatisfactory battery performance from the perspective of preparation to application,outside to inside of layered oxide cathodes,which severely limit their practical application.This work is meant to review these critical problems associated with layered oxide cathodes to understand their fundamental roots and degradation mechanisms,and to provide a comprehensive summary of mainstream modification strategies including chemical substitution,surface modification,structure modulation,and so forth,concentrating on how to improve air stability,reduce interfacial side reaction,and suppress phase transition for realizing high structural reversibility,fast Na+kinetics,and superior comprehensive electrochemical performance.The advantages and disadvantages of different strategies are discussed,and insights into future challenges and opportunities for layered oxide cathodes are also presented.展开更多
Sodium-ion batteries(SIBs) have demonstrated great application prospects in large-scale energy storage systems and low-speed electric vehicles due to the cost effectiveness and abundant resources. Layered transition-m...Sodium-ion batteries(SIBs) have demonstrated great application prospects in large-scale energy storage systems and low-speed electric vehicles due to the cost effectiveness and abundant resources. Layered transition-metal oxides are recognized as one of the most attractive sodium-ion storage cathode candidates by virtue of their high compositional diversity, environmental friendliness, ease of synthesis, and promising theoretical capacities. The practicability, however, is still limited by the fact that the energy densities of most Na-storage layered oxide cathodes solely using the conventional cationic redox are not comparable to those of the lithium-ion storage counterparts. Recently, the strategy of activating anionic redox(O^(2-)/O^(n-)) which is popular in Li-rich layered materials has been successfully applied in oxide cathodes of SIBs to promote the energy density to a new level. It is interesting to note that excess Na is not the prerequisite to induce anionic redox in sodium oxides, indicating a new mechanism underlying Na-ion materials. Herein, the latest advances on the anionic redox chemistry in layered oxide cathodes for SIBs,including the fundamental theories, triggering strategies, and applicable cathode materials, are comprehensively reviewed.Moreover, the challenges(mainly O_(2) release) facing anionic redox are discussed, and the possible remedies are outlined for future developments toward a highly reversible oxygen usage. We believe that this review can provide a valuable guidance for the exploration of high-energy layered oxide cathode materials of SIBs.展开更多
Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extracti...Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extraction process,resulting in large lattice strains which are the origin of cycledstructure degradations.Here,we demonstrate that the Na-storage lattice strains of layered oxides can be reduced by pushing charge transfer on anions(O^(2-)).Specifically,the designed O3-type Ru-based model compound,which shows an increased charge transfer on anions,displays retarded O3-P3-O1 multiple phase transitions and obviously reduced lattice strains upon cycling as directly revealed by a combination of ex situ X-ray absorption spectroscopy,in situ X-ray diffraction and geometric phase analysis.Meanwhile,the stable Na-storage lattice structure leads to a superior cycling stability with an excellent capacity retention of 84%and ultralow voltage decay of 0.2 mV/cycle after 300 cycles.More broadly,our work highlights an intrinsically structure-regulation strategy to enable a stable cycling structure of layered oxides meanwhile increasing the materials’redox activity and Nadiffusion kinetics.展开更多
P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potentia...P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potential.However,some catastrophic flaws,such as air instability,complicated multiphase evolution,and irreversible anionic redox,limit its electrochemical performance and hinder its application.Here,an air-stable single-crystal P2-type Na_(2/3)Ni_(1/3)Mn_(1/3)Ti_(1/3)O_(2)is proposed based on the multifunctional structural modulation of Ti substitution that could alleviate the issues for practical SIBs.As a result,the cathode with high energy density shows excellent air stability and highly reversible phase transitions(P2–OP4),and delivers faster kinetics and stable anion redox chemistry.Meanwhile,a thorough investigation of the relationship between structure,function,and properties is demonstrated,emphasizing formation processes,electrochemical behavior,structural evolution,and air stability.Overall,this study provides the direction of multifunctional structural modulation for the development of high-performance sodium-based layered cathode materials for practical applications.展开更多
Understanding the structural origin of the competition between oxygen 2p and transition-metal 3d orbitals in oxygen-redox(OR)layered oxides is eminently desirable for exploring reversible and high-energy-density Li/Na...Understanding the structural origin of the competition between oxygen 2p and transition-metal 3d orbitals in oxygen-redox(OR)layered oxides is eminently desirable for exploring reversible and high-energy-density Li/Na-ion cathodes.Here,we reveal the correlation between cationic ordering transition and OR degradation in ribbon-ordered P3-Na_(0.6)Li_(0.2)Mn_(0.8)O_(2) via in situ structural analysis.Comparing two different voltage windows,the OR capacity can be improved approximately twofold when suppressing the in-plane cationic ordering transition.We find that the intralayer cationic migration is promoted by electrochemical reduction from Mn^(4+)to Jahn–Teller Mn^(3+)and the concomitant NaO_(6) stacking transformation from triangular prisms to octahedra,resulting in the loss of ribbon ordering and electrochemical decay.First-principles calculations reveal that Mn^(4+)/Mn^(3+)charge ordering and alignment of the degenerate eg orbital induce lattice-level collective Jahn–Teller distortion,which favors intralayer Mn-ion migration and thereby accelerates OR degradation.These findings unravel the relationship between in-plane cationic ordering and OR reversibility and highlight the importance of superstructure protection for the rational design of reversible OR-active layered oxide cathodes.展开更多
High-performance lithium-ion batteries(LIB)are important in powering emerging technologies.Cathodes are regarded as the bottleneck of increasing battery energy density,among which layered oxides are the most promising...High-performance lithium-ion batteries(LIB)are important in powering emerging technologies.Cathodes are regarded as the bottleneck of increasing battery energy density,among which layered oxides are the most promising candidates for LIB.However,a limitation with layered oxides cathodes is the transition metal and Li site mixing,which significantly impacts battery capacity and cycling stability.Despite recent research on Li/Ni mixing,there is a lack of comprehensive understanding of the origin of cation mixing between the transition metal and Li;therefore,practical means to address it.Here,a critical review of cation mixing in layered cathodes has been provided,emphasising the understanding of cation mixing mechanisms and their impact on cathode material design.We list and compare advanced characterisation techniques to detect cation mixing in the material structure;examine methods to regulate the degree of cation mixing in layered oxides to boost battery capacity and cycling performance,and critically assess how these can be applied practically.An appraisal of future research directions,including superexchange interaction to stabilise structures and boost capacity retention has also been concluded.Findings will be of immediate benefit in the design of layered cathodes for high-performance rechargeable LIB and,therefore,of interest to researchers and manufacturers.展开更多
The pursuit of high energy density while achieving long cycle life remains a challenge in developing transition metal(TM)oxide cathode materials for sodium-ion batteries(SIBs).Here,we present a concept of precisely ma...The pursuit of high energy density while achieving long cycle life remains a challenge in developing transition metal(TM)oxide cathode materials for sodium-ion batteries(SIBs).Here,we present a concept of precisely manipulating structural evolution via local coordination chemistry regulation to design high-performance composite cathode materials.The controllable structural evolution process is realized by tuning magnesium content in Na0.6Mn1-xMgxO2,which is elucidated by a combination of experimental analysis and theoretical calculations.The substitution of Mg into Mn sites not only induces a unique structural evolu-tion from layered–tunnel structure to layered structure but also mitigates the Jahn–Teller distortion of Mn3+.Meanwhile,benefiting from the strong ionic inter-action between Mg2+and O2-,local environments around O2-coordinated with electrochemically inactive Mg2+are anchored in the TM layer,providing a pinning effect to stabilize crystal structure and smooth electrochemical profile.The layered–tunnel Na0.6Mn0.95Mg0.05O2 cathode material delivers 188.9 mAh g-1 of specific capacity,equivalent to 508.0 Wh kg-1 of energy density at 0.5C,and exhibits 71.3%of capacity retention after 1000 cycles at 5C as well as excellent compatibility with hard carbon anode.This work may provide new insights of manipulating structural evolution in composite cathode materials via local coordi-nation chemistry regulation and inspire more novel design of high-performance SIB cathode materials.展开更多
Poly(ethylene oxide)(PEO)polymer electrolytes(PEs)have been commercially applied in LiFePO_(4)||Li solid-state lithium batteries(SSLBs).However,it remains challenging to develop PEO-based PEs applicable to the high-vo...Poly(ethylene oxide)(PEO)polymer electrolytes(PEs)have been commercially applied in LiFePO_(4)||Li solid-state lithium batteries(SSLBs).However,it remains challenging to develop PEO-based PEs applicable to the high-voltage SSLBs with higher energy density,owing to the poor electrochemical stability of PEO.Herein,we report a scalable strategy for fabricating PEO-based PEs with high-voltage compatibility,by exploiting a new mechanism to stabilize the cathode-electrolyte interface in the highvoltage SSLBs.The protocol only involves a one-pot synthesis procedure to covalently crosslink the PEO chains,in the presence of high-content lithium bis(trifluoromethylsulphonyl)imide(LiTFSI)salts and N,N-dimethylformamide(DMF).LiTFSI-DMF supramolecular aggregates are formed and firmly embedded in the polymer network,endowing the PE with high room-temperature ionic conductivity.The dissociated and highly concentrated TFSI^-anions can enter the Helmholtz layer close to the high-voltage cathode,leading to the formation of a thin and homogeneous cathode electrolyte interface(CEI),mainly composed of LiF,on the cathode.The CEI with high electrochemical stability can effectively stabilize the cathode-electrolyte interface,enabling long-term stable cycling of the high-voltage LiCoO_(2)||Li and nickelrich NCM_(622)||Li batteries at room temperature.The simplicity and scalability of the strategy makes the reported PEO-based PE potentially applicable in high-voltage SSLBs in practice.展开更多
Lithium ion batteries using Ni-Co-Mn ternary oxide materials(NCMs)and Ni-Co-Al materials(NCAs)as the cathode materials are dominantly employed to power the electric vehicles(EVs).Increasing the driving range of EVs ne...Lithium ion batteries using Ni-Co-Mn ternary oxide materials(NCMs)and Ni-Co-Al materials(NCAs)as the cathode materials are dominantly employed to power the electric vehicles(EVs).Increasing the driving range of EVs necessitates an increase of Ni content to improve the energy densities,which,however,degrades the cycle stability.Here we review the doping/coating of tungsten and related elements to improve the electrochemical performance of these cathodes especially the cycle stability.The selection of tungsten and related elements is based on their special properties including the high valence state,strong bonding with oxygen and the large ionic radius.The improvement of cycle stability mainly results from two features:(1)the enhancement of bulk structure stability upon doping(Mo,W,Ta,Nb)and(2)the resistance of side reactions of electrode/electrolyte by the surficial layer induced by direct coating(V,W,Nb)or bulk doping.For the recent high Ni materials,the formation of Ni2+and its migration to the Li layer induced by these doped/coated tungsten-related elements,and the presence of spinel or rock-salt phase before cycling contributes to improving the cycle stability.The key challenges are the selection of an optimized additive concentration and the fundamental understanding of the reaction mechanism,which will provide insightful guidance for maximizing the electrochemical performance of the state-of-the-art lithium-ion batteries at minimal additional process costs.展开更多
The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hyd...The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hydride(Ni-MH)batteries,to the Ni-rich cathode featured in lithium-ion batteries(LIBs).Ni-based alkaline batteries were first invented in the 1900s,and the well-developed Ni-MH batteries were used on a large scale in Toyota Prius vehicles in the mid-1990s.Around the same time,however,Sony Corporation commercialized the first LIBs in camcorders.After temporally fading as LiCoO_(2) dominated the cathode in LIBs,nickel oxide-based cathodes eventually found their way back to the mainstreaming battery industry.The uniqueness of Ni in batteries is that it helps to deliver high energy density and great storage capacity at a low cost.This review mainly provides a comprehensive overview of the key role of Ni-based cathodes in rechargeable batteries.After presenting the physical and chemical properties of the 3d transition-metal Ni,which make it an optimal cationic redox center in the cathode of batteries,we introduce the structure,reaction mechanism,and modification of nickel hydroxide electrode in Ni-Cd and Ni-MH rechargeable batteries.We then move on to the Ni-based layered oxide cathode in LIBs,with a focus on the structure,issues,and challenges of layered oxides,LiNiO_(2),and LiNi_(1−x−y)Co_(x)Mn_(y)O_(2).The role of Ni in the electrochemical performance and thermal stability of the Ni-rich cathode is highlighted.By bridging the“old”Ni-based batteries and the“modern”Ni-rich cathode in the LIBs,this review is committed to providing insights into the Ni-based electrochemistry and material design,which have been under research and development for over 100 years.This overview would shed new light on the development of advanced Ni-containing batteries with high energy density and long cycle life.展开更多
Transition metal oxide cathodes such as layered Li Co O_(2),spinel Li Mn_(2)O_(4) and olivine Li Fe PO4 have been commercialized for several decades and widely used in the rechargeable Li-ion batteries(LIBs).While gre...Transition metal oxide cathodes such as layered Li Co O_(2),spinel Li Mn_(2)O_(4) and olivine Li Fe PO4 have been commercialized for several decades and widely used in the rechargeable Li-ion batteries(LIBs).While great theoretical efforts have been made using the density functional theory(DFT)method,leading to insightful understanding covering materials stability and functional properties,the lack of consistency in choices of functionals and/or convergence criteria makes it somewhat difficult to compare results.It is therefore highly useful to assess these established systems towards self-consistency,thus offering a reliable working basis for theoretical formulation of novel cathodes.Here in this work,we have carried out systematic DFT calculations on the basis of recently established framework covering both thermodynamic stability,functional properties and associated mechanisms.Efforts have been made in selfconsistent selection of exchange-correlation(XC)functionals in terms of dependable accuracy with affordable computational cost,which is essential for high-throughput first-principles calculations.The outcome of the current work on three established cathode systems is in very good agreement with experimental data,and the methodology is to provide a solid basis for designing novel cathode materials without using costing non-local exchange-correlation functionals for structure-energy calculations.展开更多
Research on the chemistry of high-energy-density transition metal oxide cathodes(TMOCs)is at the forefront in the pursuit of lithium-ion batteries with increased energy density.As a critical component of these cathode...Research on the chemistry of high-energy-density transition metal oxide cathodes(TMOCs)is at the forefront in the pursuit of lithium-ion batteries with increased energy density.As a critical component of these cathodes,binders not only glue cathode active material particles and conducting carbons together and to current collectors but also play pivotal roles in building multiscale compatible interphases between electrolytes and cathodes.In this review,we outline several vital design considerations of high-voltage binders,several of which are already present in traditional binder design that need to be highlighted,and systematically reveal the chemistry and mechanisms underpinning such binders for in-depth understanding.Further optimization of the design of polymer binders to improve battery performance is also discussed.Finally,perspec-tives regarding the future rational design and promising research opportunities of state-of-the-art binders for high-voltage TMOCs are presented.展开更多
Li and Mn rich(LMR)layered oxides,written as xLi_(2) MnO_(3)·(1-x)LiMO_(2)(M=Mn,Ni,Co,Fe,etc.),have been widely reported in recent years due to their high capacity and high energy density.The stable structure and...Li and Mn rich(LMR)layered oxides,written as xLi_(2) MnO_(3)·(1-x)LiMO_(2)(M=Mn,Ni,Co,Fe,etc.),have been widely reported in recent years due to their high capacity and high energy density.The stable structure and superior performance of LMR oxides make them one of the most promising candidates for the next-generation cathode materials.However,the commercialization of these materials is hindered by several drawbacks,such as low initial Coulombic efficiency,the degradation of voltage and capacity during cycling,and poor rate performance.This review summarizes research progress in solving these concerns of LMR cathodes over the past decade by following three classes of strategies:morphology design,bulk design,and surface modification.We elaborate on the processing procedures,electrochemical performance,mechanisms,and limitations of each approach,and finally put forward the concerns left and the possible solutions for the commercialization of LMR cathodes.展开更多
基金supported by the National Key R&D Program of China(Grant No.2018YFB0905400)the National Natural Science Foundation of China(Grant Nos.51872303,U1964205,51902321)+4 种基金the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD18E020004,LY18E020018)the Ningbo S&T Innovation 2025 Major Special Programme(Grant Nos.2018B10061,2018B10087,2019B10044)the Natural Science Foundation of Ningbo(Grant Nos.2018A610010,2019A610007)the Jiangxi Provincial Key R&D Program of China(Grant No.20182ABC28007)the Youth Innovation Promotion Association CAS(2017342).
文摘All-solid-state lithium batteries(ASSLBs)have attracted increasing attention due to their high safety and energy density.Among all corresponding solid electrolytes,sulfide electrolytes are considered to be the most promising ion conductors due to high ionic conductivities.Despite this,many challenges remain in the application of ASSLBs,including the stability of sulfide electrolytes,complex interfacial issues between sulfide electrolytes and oxide electrodes as well as unstable anodic interfaces.Although oxide cathodes remain the most viable electrode materials due to high stability and industrialization degrees,the matching of sulfide electrolytes with oxide cathodes is challenging for commercial use in ASSLBs.Based on this,this review will present an overview of emerging ASSLBs based on sulfide electrolytes and oxide cathodes and high-light critical properties such as compatible electrolyte/electrode interfaces.And by considering the current challenges and opportunities of sulfide electrolyte-based ASSLBs,possible research directions and perspectives are discussed.
基金supported by the National Natural Science Foundation of China (22179021)the Basic Science Center Project of National Natural Science Foundation of China (51788104)+1 种基金the Natural Science Foundation of Fujian Province (2019J01284)21C Innovation Laboratory Contemporary Amperex Technology Ltd (21C-OP-202011)。
文摘Sodium-ion batteries have the potential to be an alternative to lithium-ion batteries especially for applications such as large-scale grid energy storage. The development of suitable cathode materials is crucial to the commercialization of sodium-ion batteries.Sodium-based layered-type transition metal oxides are promising candidates as cathode materials as they offer decent energy density and are easy to be synthesized. Unfortunately, most layered oxides suffer from poor air-stability, which greatly increases the cost of manufacturing and handling. The air-sensitivity severely limits the development and commercial application of sodium-ion batteries. A review that summarizes the latest understanding and solutions of air-sensitivity is desired. In this review,the background and fundamentals of sodium-based layered-type cathode materials are presented, followed by a discussion on the latest research on air-sensitivity of these materials. The mechanism is complex and involves multiple chemical and physical reactions. Various strategies are shown to alleviate some of the corresponding problems and promote the feasible application of sodium-ion batteries, followed by an outlook on current and future research directions of air-stable cathode materials. It is believed that this review will provide insights for researchers to develop practically relevant materials for sodium-ion batteries.
基金supported by the National Natural Science Foundation of China(51971124,52171217)the State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University(EIPE22208)+5 种基金the National Postdoctoral Program for Innovative Talents(BX20200222)the China Postdoctoral Science Foundation(2020M682878)Zhejiang Natural Science Foundation(LQ23E020002)Wenzhou Natural Science Foundation(G20220019)Cooperation between industry and education project of Ministry of Education(220601318235513)National Natural Science Foundation of China(52202284)。
文摘Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides distinguish themselves from the mains cathode materials of SIBs owing to their advantages such as high specific capacity,simple synthesis route,and environmental benignity.However,the commercial development of the layered oxides is limited by sluggish kinetics,complex phase transition and poor air stability.Based on the research ideas from macro-to micro-scale,this review systematically summarizes the current optimization strategies of sodium-ion layered oxide cathodes(SLOC)from different dimensions:microstructure design,local chemistry regulation and structural unit construction.In the dimension of microstructure design,the various structures such as the microspheres,nanoplates,nanowires and exposed active facets are prepared to improve the slow kinetics and electrochemical performance.Besides,from the view of local chemistry regulation by chemical element substitution,the intrinsic electron/ion properties of SLOC have been enhanced to strengthen the structural stability.Furthermore,the optimization idea of endeavors to regulate the physical and chemical properties of cathode materials essentially is put forward from the dimension of structural unit construction.The opinions and strategies proposed in this review will provide some inspirations for the design of new SLOC in the future.
基金This work was supported by the National Key Research and Development Programs(Grant No.2021YFB2400400)National Natural Science Foundation of China(Grant Nos.51772093,52202284)+5 种基金Major Science and Technology Innovation Project of Hunan Province(Grant No.2020GK1010-2020GK1014-4)Distinguished Youth Foun-dation of Hunan Province(Grant No.2019JJ20010)Zhejiang Natural Science Foundation(Grant No.LQ23E020002)Wenzhou Natural Science Foundation(Grant No.G20220019)Cooperation between industry and education project of Ministry of Education(Grant No.220601318235513)State Key Laboratory of Elec-trical Insulation and Power Equipment,Xi'an Jiaotong University(Grant No.EIPE22208).
文摘Sodium-ion batteries(SIBs)are considered as a low-cost complementary or alternative system to prestigious lithium-ion batteries(LIBs)because of their similar working principle to LIBs,cost-effectiveness,and sustainable availability of sodium resources,especially in large-scale energy storage systems(EESs).Among various cathode candidates for SIBs,Na-based layered transition metal oxides have received extensive attention for their relatively large specific capacity,high operating potential,facile synthesis,and environmental benignity.However,there are a series of fatal issues in terms of poor air stability,unstable cathode/electrolyte interphase,and irreversible phase transition that lead to unsatisfactory battery performance from the perspective of preparation to application,outside to inside of layered oxide cathodes,which severely limit their practical application.This work is meant to review these critical problems associated with layered oxide cathodes to understand their fundamental roots and degradation mechanisms,and to provide a comprehensive summary of mainstream modification strategies including chemical substitution,surface modification,structure modulation,and so forth,concentrating on how to improve air stability,reduce interfacial side reaction,and suppress phase transition for realizing high structural reversibility,fast Na+kinetics,and superior comprehensive electrochemical performance.The advantages and disadvantages of different strategies are discussed,and insights into future challenges and opportunities for layered oxide cathodes are also presented.
基金financially supported by the National Natural Science Foundation of China(21805007,21825102,22075016,and 21731001)the National Key Research and Development Program of China(2018YFA0703702)+1 种基金the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST,2018QNRC001)the Fundamental Research Funds for the Central Universities(FRF-TP20-020A3)。
文摘Sodium-ion batteries(SIBs) have demonstrated great application prospects in large-scale energy storage systems and low-speed electric vehicles due to the cost effectiveness and abundant resources. Layered transition-metal oxides are recognized as one of the most attractive sodium-ion storage cathode candidates by virtue of their high compositional diversity, environmental friendliness, ease of synthesis, and promising theoretical capacities. The practicability, however, is still limited by the fact that the energy densities of most Na-storage layered oxide cathodes solely using the conventional cationic redox are not comparable to those of the lithium-ion storage counterparts. Recently, the strategy of activating anionic redox(O^(2-)/O^(n-)) which is popular in Li-rich layered materials has been successfully applied in oxide cathodes of SIBs to promote the energy density to a new level. It is interesting to note that excess Na is not the prerequisite to induce anionic redox in sodium oxides, indicating a new mechanism underlying Na-ion materials. Herein, the latest advances on the anionic redox chemistry in layered oxide cathodes for SIBs,including the fundamental theories, triggering strategies, and applicable cathode materials, are comprehensively reviewed.Moreover, the challenges(mainly O_(2) release) facing anionic redox are discussed, and the possible remedies are outlined for future developments toward a highly reversible oxygen usage. We believe that this review can provide a valuable guidance for the exploration of high-energy layered oxide cathode materials of SIBs.
基金supported by the National Natural Science Foundation of China(Grant No.12105197 and 52088101)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010319)+1 种基金the open research fund of Songshan Lake Materials Laboratory(No.2022SLABFK04)Large Scientific Facility Open Subject of Songshan Lake,Dongguan,Guangdong
文摘Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extraction process,resulting in large lattice strains which are the origin of cycledstructure degradations.Here,we demonstrate that the Na-storage lattice strains of layered oxides can be reduced by pushing charge transfer on anions(O^(2-)).Specifically,the designed O3-type Ru-based model compound,which shows an increased charge transfer on anions,displays retarded O3-P3-O1 multiple phase transitions and obviously reduced lattice strains upon cycling as directly revealed by a combination of ex situ X-ray absorption spectroscopy,in situ X-ray diffraction and geometric phase analysis.Meanwhile,the stable Na-storage lattice structure leads to a superior cycling stability with an excellent capacity retention of 84%and ultralow voltage decay of 0.2 mV/cycle after 300 cycles.More broadly,our work highlights an intrinsically structure-regulation strategy to enable a stable cycling structure of layered oxides meanwhile increasing the materials’redox activity and Nadiffusion kinetics.
基金supported by the National Natural Science Foundation of China(52250710680,51971124,52171217,52202284)Hunan Provincial Science and Technology Innovation Major Project(2020GK1010-2020GK1014-4)+7 种基金Zhejiang Provincial Natural Science Foundation(LZ21E010001,LQ23E020002)Science and Technology Project of State Grid Corporation of China(5419-202158503A-0-5-ZN)Wenzhou key scientific and technological innovation research projects(ZG2023053)Wenzhou Natural Science Foundation(ZG2022032,G20220019,G20220021)Cooperation between industry and education project of Ministry of Education(220601318235513)State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University(EIPE22208)the China Scholarship Council(202106370062)Doctoral Innovation Foundation of Wenzhou University(3162023001001)。
文摘P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potential.However,some catastrophic flaws,such as air instability,complicated multiphase evolution,and irreversible anionic redox,limit its electrochemical performance and hinder its application.Here,an air-stable single-crystal P2-type Na_(2/3)Ni_(1/3)Mn_(1/3)Ti_(1/3)O_(2)is proposed based on the multifunctional structural modulation of Ti substitution that could alleviate the issues for practical SIBs.As a result,the cathode with high energy density shows excellent air stability and highly reversible phase transitions(P2–OP4),and delivers faster kinetics and stable anion redox chemistry.Meanwhile,a thorough investigation of the relationship between structure,function,and properties is demonstrated,emphasizing formation processes,electrochemical behavior,structural evolution,and air stability.Overall,this study provides the direction of multifunctional structural modulation for the development of high-performance sodium-based layered cathode materials for practical applications.
基金funding supports from the National Key R&D Program of China(Grant Nos.2022YFB2404400 and 2019YFA0308500)Beijing Natural Science Foundation(Z190010)National Natural Science Foundation of China(Grant Nos.51991344,52025025,52072400,and 52002394)。
文摘Understanding the structural origin of the competition between oxygen 2p and transition-metal 3d orbitals in oxygen-redox(OR)layered oxides is eminently desirable for exploring reversible and high-energy-density Li/Na-ion cathodes.Here,we reveal the correlation between cationic ordering transition and OR degradation in ribbon-ordered P3-Na_(0.6)Li_(0.2)Mn_(0.8)O_(2) via in situ structural analysis.Comparing two different voltage windows,the OR capacity can be improved approximately twofold when suppressing the in-plane cationic ordering transition.We find that the intralayer cationic migration is promoted by electrochemical reduction from Mn^(4+)to Jahn–Teller Mn^(3+)and the concomitant NaO_(6) stacking transformation from triangular prisms to octahedra,resulting in the loss of ribbon ordering and electrochemical decay.First-principles calculations reveal that Mn^(4+)/Mn^(3+)charge ordering and alignment of the degenerate eg orbital induce lattice-level collective Jahn–Teller distortion,which favors intralayer Mn-ion migration and thereby accelerates OR degradation.These findings unravel the relationship between in-plane cationic ordering and OR reversibility and highlight the importance of superstructure protection for the rational design of reversible OR-active layered oxide cathodes.
基金the Australian Institute of Nuclear Science and Engineering (AINSE) Limited for providing financial assistance in the form of a Post Graduate Research Award (PGRA) to carry out this worksupported by the Australian Research Council under grants DP200101862, DP210101486, and FL210100050
文摘High-performance lithium-ion batteries(LIB)are important in powering emerging technologies.Cathodes are regarded as the bottleneck of increasing battery energy density,among which layered oxides are the most promising candidates for LIB.However,a limitation with layered oxides cathodes is the transition metal and Li site mixing,which significantly impacts battery capacity and cycling stability.Despite recent research on Li/Ni mixing,there is a lack of comprehensive understanding of the origin of cation mixing between the transition metal and Li;therefore,practical means to address it.Here,a critical review of cation mixing in layered cathodes has been provided,emphasising the understanding of cation mixing mechanisms and their impact on cathode material design.We list and compare advanced characterisation techniques to detect cation mixing in the material structure;examine methods to regulate the degree of cation mixing in layered oxides to boost battery capacity and cycling performance,and critically assess how these can be applied practically.An appraisal of future research directions,including superexchange interaction to stabilise structures and boost capacity retention has also been concluded.Findings will be of immediate benefit in the design of layered cathodes for high-performance rechargeable LIB and,therefore,of interest to researchers and manufacturers.
基金National Natural Science Foundation of China,Grant/Award Numbers:51772093,51971124,52171217,52202284National Key Research and Devel opment Programs,Grant/Award Number:2021YFB2400400+4 种基金Zhejiang Natural Science Foundation,Grant/Award Number:LQ23E020002WenZhou Natural Science Foundation,Grant/Award Numbers:G20220019,G20220021State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Grant/Award Number.EIPE22208Cooperation between Industry and Education Project of Ministry of Education,Grant/Award Number:220601318235513Doctoral Innovation Foundation of Wenzhou University,Grant/Award Number.3162023001001。
文摘The pursuit of high energy density while achieving long cycle life remains a challenge in developing transition metal(TM)oxide cathode materials for sodium-ion batteries(SIBs).Here,we present a concept of precisely manipulating structural evolution via local coordination chemistry regulation to design high-performance composite cathode materials.The controllable structural evolution process is realized by tuning magnesium content in Na0.6Mn1-xMgxO2,which is elucidated by a combination of experimental analysis and theoretical calculations.The substitution of Mg into Mn sites not only induces a unique structural evolu-tion from layered–tunnel structure to layered structure but also mitigates the Jahn–Teller distortion of Mn3+.Meanwhile,benefiting from the strong ionic inter-action between Mg2+and O2-,local environments around O2-coordinated with electrochemically inactive Mg2+are anchored in the TM layer,providing a pinning effect to stabilize crystal structure and smooth electrochemical profile.The layered–tunnel Na0.6Mn0.95Mg0.05O2 cathode material delivers 188.9 mAh g-1 of specific capacity,equivalent to 508.0 Wh kg-1 of energy density at 0.5C,and exhibits 71.3%of capacity retention after 1000 cycles at 5C as well as excellent compatibility with hard carbon anode.This work may provide new insights of manipulating structural evolution in composite cathode materials via local coordi-nation chemistry regulation and inspire more novel design of high-performance SIB cathode materials.
基金the National Key R&D Program of China(No.2018YFC1105401)for the financial support。
文摘Poly(ethylene oxide)(PEO)polymer electrolytes(PEs)have been commercially applied in LiFePO_(4)||Li solid-state lithium batteries(SSLBs).However,it remains challenging to develop PEO-based PEs applicable to the high-voltage SSLBs with higher energy density,owing to the poor electrochemical stability of PEO.Herein,we report a scalable strategy for fabricating PEO-based PEs with high-voltage compatibility,by exploiting a new mechanism to stabilize the cathode-electrolyte interface in the highvoltage SSLBs.The protocol only involves a one-pot synthesis procedure to covalently crosslink the PEO chains,in the presence of high-content lithium bis(trifluoromethylsulphonyl)imide(LiTFSI)salts and N,N-dimethylformamide(DMF).LiTFSI-DMF supramolecular aggregates are formed and firmly embedded in the polymer network,endowing the PE with high room-temperature ionic conductivity.The dissociated and highly concentrated TFSI^-anions can enter the Helmholtz layer close to the high-voltage cathode,leading to the formation of a thin and homogeneous cathode electrolyte interface(CEI),mainly composed of LiF,on the cathode.The CEI with high electrochemical stability can effectively stabilize the cathode-electrolyte interface,enabling long-term stable cycling of the high-voltage LiCoO_(2)||Li and nickelrich NCM_(622)||Li batteries at room temperature.The simplicity and scalability of the strategy makes the reported PEO-based PE potentially applicable in high-voltage SSLBs in practice.
基金financially supported by the Australian CRC-P project“Value-added cobalt refining technologies powering advanced batteries”,administered by Pure Battery Technologies Pty LtdAustralian Research Council through its Laureate Fellowship and Linkage Projects
文摘Lithium ion batteries using Ni-Co-Mn ternary oxide materials(NCMs)and Ni-Co-Al materials(NCAs)as the cathode materials are dominantly employed to power the electric vehicles(EVs).Increasing the driving range of EVs necessitates an increase of Ni content to improve the energy densities,which,however,degrades the cycle stability.Here we review the doping/coating of tungsten and related elements to improve the electrochemical performance of these cathodes especially the cycle stability.The selection of tungsten and related elements is based on their special properties including the high valence state,strong bonding with oxygen and the large ionic radius.The improvement of cycle stability mainly results from two features:(1)the enhancement of bulk structure stability upon doping(Mo,W,Ta,Nb)and(2)the resistance of side reactions of electrode/electrolyte by the surficial layer induced by direct coating(V,W,Nb)or bulk doping.For the recent high Ni materials,the formation of Ni2+and its migration to the Li layer induced by these doped/coated tungsten-related elements,and the presence of spinel or rock-salt phase before cycling contributes to improving the cycle stability.The key challenges are the selection of an optimized additive concentration and the fundamental understanding of the reaction mechanism,which will provide insightful guidance for maximizing the electrochemical performance of the state-of-the-art lithium-ion batteries at minimal additional process costs.
基金financially supported by the China Postdoctoral Science Foundation(No.2021M700396)the National Natural Science Foundation of China(No.52102206)。
文摘The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hydride(Ni-MH)batteries,to the Ni-rich cathode featured in lithium-ion batteries(LIBs).Ni-based alkaline batteries were first invented in the 1900s,and the well-developed Ni-MH batteries were used on a large scale in Toyota Prius vehicles in the mid-1990s.Around the same time,however,Sony Corporation commercialized the first LIBs in camcorders.After temporally fading as LiCoO_(2) dominated the cathode in LIBs,nickel oxide-based cathodes eventually found their way back to the mainstreaming battery industry.The uniqueness of Ni in batteries is that it helps to deliver high energy density and great storage capacity at a low cost.This review mainly provides a comprehensive overview of the key role of Ni-based cathodes in rechargeable batteries.After presenting the physical and chemical properties of the 3d transition-metal Ni,which make it an optimal cationic redox center in the cathode of batteries,we introduce the structure,reaction mechanism,and modification of nickel hydroxide electrode in Ni-Cd and Ni-MH rechargeable batteries.We then move on to the Ni-based layered oxide cathode in LIBs,with a focus on the structure,issues,and challenges of layered oxides,LiNiO_(2),and LiNi_(1−x−y)Co_(x)Mn_(y)O_(2).The role of Ni in the electrochemical performance and thermal stability of the Ni-rich cathode is highlighted.By bridging the“old”Ni-based batteries and the“modern”Ni-rich cathode in the LIBs,this review is committed to providing insights into the Ni-based electrochemistry and material design,which have been under research and development for over 100 years.This overview would shed new light on the development of advanced Ni-containing batteries with high energy density and long cycle life.
基金supported in part by the 1000 Talents Program of Chinathe Zhengzhou Materials Genome Institute+2 种基金the National Natural Science Foundation of China(No.51001091,51571182,111174256,91233101,51602094,11274100)the Fundamental Research Program from the Ministry of Science and Technology of China(No.2014CB931704)the Program for Science&Technology Innovation Talents in the Universities of Henan Province(18HASTIT009)。
文摘Transition metal oxide cathodes such as layered Li Co O_(2),spinel Li Mn_(2)O_(4) and olivine Li Fe PO4 have been commercialized for several decades and widely used in the rechargeable Li-ion batteries(LIBs).While great theoretical efforts have been made using the density functional theory(DFT)method,leading to insightful understanding covering materials stability and functional properties,the lack of consistency in choices of functionals and/or convergence criteria makes it somewhat difficult to compare results.It is therefore highly useful to assess these established systems towards self-consistency,thus offering a reliable working basis for theoretical formulation of novel cathodes.Here in this work,we have carried out systematic DFT calculations on the basis of recently established framework covering both thermodynamic stability,functional properties and associated mechanisms.Efforts have been made in selfconsistent selection of exchange-correlation(XC)functionals in terms of dependable accuracy with affordable computational cost,which is essential for high-throughput first-principles calculations.The outcome of the current work on three established cathode systems is in very good agreement with experimental data,and the methodology is to provide a solid basis for designing novel cathode materials without using costing non-local exchange-correlation functionals for structure-energy calculations.
基金This work was financially supported by the NSFC-Shandong Joint Fund(U1706229)the Science Foundation for the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA22010603)+1 种基金the National Natural Science Foundation of China(51803230)the Qingdao Key Laboratory of Solar Energy Utilization and Energy Storage Technology.
文摘Research on the chemistry of high-energy-density transition metal oxide cathodes(TMOCs)is at the forefront in the pursuit of lithium-ion batteries with increased energy density.As a critical component of these cathodes,binders not only glue cathode active material particles and conducting carbons together and to current collectors but also play pivotal roles in building multiscale compatible interphases between electrolytes and cathodes.In this review,we outline several vital design considerations of high-voltage binders,several of which are already present in traditional binder design that need to be highlighted,and systematically reveal the chemistry and mechanisms underpinning such binders for in-depth understanding.Further optimization of the design of polymer binders to improve battery performance is also discussed.Finally,perspec-tives regarding the future rational design and promising research opportunities of state-of-the-art binders for high-voltage TMOCs are presented.
基金financially supported by the National Key R&D Program of China(2016YFB0700600)the Soft Science Research Project of Guangdong Province(No.2017B030301013)the Shenzhen Science and Technology Research Grant(ZDSYS201707281026184)。
文摘Li and Mn rich(LMR)layered oxides,written as xLi_(2) MnO_(3)·(1-x)LiMO_(2)(M=Mn,Ni,Co,Fe,etc.),have been widely reported in recent years due to their high capacity and high energy density.The stable structure and superior performance of LMR oxides make them one of the most promising candidates for the next-generation cathode materials.However,the commercialization of these materials is hindered by several drawbacks,such as low initial Coulombic efficiency,the degradation of voltage and capacity during cycling,and poor rate performance.This review summarizes research progress in solving these concerns of LMR cathodes over the past decade by following three classes of strategies:morphology design,bulk design,and surface modification.We elaborate on the processing procedures,electrochemical performance,mechanisms,and limitations of each approach,and finally put forward the concerns left and the possible solutions for the commercialization of LMR cathodes.
