Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despit...Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despite the extensive exploration of electrode materials,the relatively low attainable capacity of NIBs hinders their practical application.In recent years,the anionic redox reaction(ARR)in NIBs has been emerging as a new paradigm to deliver extra capacity and thus offers an opportunity to break through the intrinsic energy density limit.In this review,the fundamental investigation of the ARR mechanism and the latest exploration of cathode materials are summarized,in order to highlight the significance of reversible anionic redox and suggest prospective developing directions.展开更多
A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plate...A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.展开更多
Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surf...Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surface.Oxygen release has been widely accepted as the ringleader of surficial structure instability.However,the role of TM in surface stability has been much overlooked,not to mention its interplay with oxygen release.Herein,TM dissolution and oxygen release are comparatively investigated in Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2).Ni is verified to detach from the lattice counter-intuitively despite the overwhelming stoichiometry of Mn,facilitating subsequent oxygen release of the ARR process.Intriguingly,surface reorganization occurs following regulated Ni dissolution,enabling the stabilization of the surface and elimination of oxygen release in turn.Accordingly,a novel optimization strategy is proposed by adding a relaxation step at 4.50 V within the first cycle procedure.Battery performance can be effectively improved,with voltage decay suppressed from 3.44 mV/cycle to 1.60 mV/cycle,and cycle stability improved from 66.77%to 90.01%after 100 cycles.This work provides new perspectives for clarifying ARR surface instability and guidance for optimizing ARR performance.展开更多
Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batt...Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.展开更多
The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,includin...The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,including a low capacity retention,large voltage hysteresis,and low rate capability.Herein,we proposed a high-Na content honeycomb-ordered cathode,P2–Na_(5/6)[Li_(1/6)Cu_(1/6)Mn_(2/3)]O_(2)(P2-NLCMO),with combined cationic/anionic redox.Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6322 symmetry.In addition,advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers,achieving fully active Cu^(3+)/Cu^(2+) redox and stabilized ARR with interactively suppressed local distortion.With a meticulously regulated charge/discharge protocol,both the cycling and rate capability of P2-NLCMO were significantly.展开更多
The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction...The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction in layered oxides has significant voltage hysteresis and decay that reduce battery performance and limit commercialization.Here,we critically review the up-todate development of anionic redox reaction in layered oxide cathodes,summarize the proposed reaction mechanism,and unveil their connection to voltage hysteresis and decay based on the state-of-the-art progress.In addition,advances associated with various modification approaches to mitigate the voltage hysteresis/decay in layered transition metal oxide cathodes are also included.Finally,we conclude with an appraisal of further research directions including rational design of high-performance layered oxide cathodes with reversible anionic redox reactions and suppressed voltage hysteresis/decay.Findings will be of immediate benefit to the development of layered oxide cathodes for high performance rechargeable batteries.展开更多
Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stab...Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stability restricts its practical application.The capacity decay of Na_(0.67)Fe_(0.6)Mn_(0.5)O_(2) mainly originates from the irreversible anionic redox reaction charge compensation due to the high-level hybridization between oxygen and iron.Herein,we rationally design a surface Ti doping strategy to tune the anionic redox reaction activity of Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) and improve its Na-storage properties.The doped Ti ions not only enlarge the Na migration spacing layer but also improve the structure stability thanks to the strong Ti-O bond.More importantly,the d0-shell electronic structure of Ti^(4+) can suppress the charge transfer from the oxidized anions to cations,thus reducing the anionic redox reaction activity and enhancing the reversibility of charge compensation.The modified Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) cathode shows a reversible capacity of 198 mA h g^(-1) and an increased capacity retention from 15% to 73% after about1 month of cycling.Meanwhile,a superior Na-ion diffusion kinetics and rate capability are also observed.This work advances the commercialization process of Na-based layered iron-manganese oxide cathodes;on the other hand,the proposed modification strategy paves the way for the design of high-performance electrode materials relying on anionic redox reactions.展开更多
Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at h...Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at high voltage.In this work,the strategy of the electron donor was utilized to address this issue.Remarkably,the earth-abundant P2-layered cathode Na_(2/3)Al_(1/6)Fe_(1/6)Mn_(2/3)O_(2)with the presence of K_(2)S renders superior rate capability(187.4 and 79.5 mA h g^(-1)at 20 and 1000 mA g^(-1))and cycling stability(a capacity retention of 85.6% over 300 cycles at 1000 mA g^(-1))within the voltage region of 2-4.4 V Na^(+)/Na.Furthermore,excellent electrochemical performance is also demonstrated in the full cell.Detailed structural analysis of as-proposed composite cathode illustrates that even at 4.4 V irreversible phase transition can be avoided as well as a cell volume variation of only 0.88%,which are attributed to the enhanced performance compared with the control group.Meanwhile,further investigation of charge compensation reveals the crucial role of sulfur ions in actively control of reversible redox reaction of oxygen species in the lattice structure.This work inspires a new strategy to enhance the structural stability of layered sodium ion cathode materials at high voltages.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
Anionic redox reaction(ARR) in layered manganese-based oxide cathodes has been considered as an effective strategy to improve the energy density of sodium-ion batteries.Mn-vacancy layered oxides deliver a high ARR-rel...Anionic redox reaction(ARR) in layered manganese-based oxide cathodes has been considered as an effective strategy to improve the energy density of sodium-ion batteries.Mn-vacancy layered oxides deliver a high ARR-related capacity with small voltage hysteresis,however,they are limited by rapid capacity degradation and poor rate capability,which arise from inferior structure changes due to repeated redox of lattice oxygen.Herein,redox-inactive Ti^(4+)is introduced to substitute partial Mn^(4+)to form Na_(2) Ti_(0.5)Mn_(2.5)O_7(Na_(4/7)[□_(1/7)Ti_(1/7)Mn_(5/7)]O_(2),□ for Mn vacancies),which can effectively restrain unfavorable interlayer gliding of Na2 Mn307 at high charge voltages,as reflected by an ultralow-strain volume variation of 0.11%.There is no irreversible O_(2) evolution observed in Na_(2) Ti_(0.5)Mn_(2.5)O_7 upon charging,which stabilizes the lattice oxygen and ensures the overall structural stability.It exhibits increased capacity retention of 79.1% after 60 cycles in Na_(2) Ti_(0.5)Mn_(2.5)O_7(17.1% in Na_(2) Mn_(3) O_7) and good rate capability(92.1 mAh g^(-1) at 0.5 A g^(-1)).This investigation provides new insights into designing high-performance cathode materials with reversible ARR and structural stability for SIBs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51725206 and 52002394)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21070500).
文摘Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despite the extensive exploration of electrode materials,the relatively low attainable capacity of NIBs hinders their practical application.In recent years,the anionic redox reaction(ARR)in NIBs has been emerging as a new paradigm to deliver extra capacity and thus offers an opportunity to break through the intrinsic energy density limit.In this review,the fundamental investigation of the ARR mechanism and the latest exploration of cathode materials are summarized,in order to highlight the significance of reversible anionic redox and suggest prospective developing directions.
基金supported by funding from Science and Technology Project of the State Grid Corporation of China("research on key technology of low-strain layered oxides for long-life Na-ion batteries",No.DG71-16-027)
文摘A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.
基金supported by the National Key Research and Development Program (2019YFA0405601)National Science Foundation of China(No. 22309097, 22179066, 21902179)+1 种基金Shandong Provincial Natural Science Foundation (2023KJ228, ZR2021QE061, ZR202103010205)the Startup Foundation for Advanced Talents in Qingdao University (DC2000005106)
文摘Anionic redox reaction(ARR)can provide extra capacity beyond transition metal(TM)redox in lithium-rich TM oxide cathodes.Practical ARR application is much hindered by the structure instability,particularly at the surface.Oxygen release has been widely accepted as the ringleader of surficial structure instability.However,the role of TM in surface stability has been much overlooked,not to mention its interplay with oxygen release.Herein,TM dissolution and oxygen release are comparatively investigated in Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2).Ni is verified to detach from the lattice counter-intuitively despite the overwhelming stoichiometry of Mn,facilitating subsequent oxygen release of the ARR process.Intriguingly,surface reorganization occurs following regulated Ni dissolution,enabling the stabilization of the surface and elimination of oxygen release in turn.Accordingly,a novel optimization strategy is proposed by adding a relaxation step at 4.50 V within the first cycle procedure.Battery performance can be effectively improved,with voltage decay suppressed from 3.44 mV/cycle to 1.60 mV/cycle,and cycle stability improved from 66.77%to 90.01%after 100 cycles.This work provides new perspectives for clarifying ARR surface instability and guidance for optimizing ARR performance.
基金supported by the National Key Research and Development Program of China (2016YFA202500)the “One Hundred Talent Project” of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (11675255)
文摘Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.
基金supported by the National Natural Science Foundation(NSFC)of China(52002394)Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020006).
文摘The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,including a low capacity retention,large voltage hysteresis,and low rate capability.Herein,we proposed a high-Na content honeycomb-ordered cathode,P2–Na_(5/6)[Li_(1/6)Cu_(1/6)Mn_(2/3)]O_(2)(P2-NLCMO),with combined cationic/anionic redox.Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6322 symmetry.In addition,advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers,achieving fully active Cu^(3+)/Cu^(2+) redox and stabilized ARR with interactively suppressed local distortion.With a meticulously regulated charge/discharge protocol,both the cycling and rate capability of P2-NLCMO were significantly.
基金the support of China Scholarship Council(No.202108430035)G.M.L.acknowledges the Australian Institute of Nuclear Science and Engineering(AINSE)Limited for financial assistance in the form of a Post Graduate Research Award(PGRA)supported by the Australian Research Council(Nos.DP200101862,DP210101486,and FL210100050).
文摘The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction in layered oxides has significant voltage hysteresis and decay that reduce battery performance and limit commercialization.Here,we critically review the up-todate development of anionic redox reaction in layered oxide cathodes,summarize the proposed reaction mechanism,and unveil their connection to voltage hysteresis and decay based on the state-of-the-art progress.In addition,advances associated with various modification approaches to mitigate the voltage hysteresis/decay in layered transition metal oxide cathodes are also included.Finally,we conclude with an appraisal of further research directions including rational design of high-performance layered oxide cathodes with reversible anionic redox reactions and suppressed voltage hysteresis/decay.Findings will be of immediate benefit to the development of layered oxide cathodes for high performance rechargeable batteries.
基金supported by the National Natural Science Foundation of China (Grant No. 12105197)the Science Center of the National Science Foundation of China (Grant No. 52088101)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant ZDKYYQ20170001)。
文摘Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stability restricts its practical application.The capacity decay of Na_(0.67)Fe_(0.6)Mn_(0.5)O_(2) mainly originates from the irreversible anionic redox reaction charge compensation due to the high-level hybridization between oxygen and iron.Herein,we rationally design a surface Ti doping strategy to tune the anionic redox reaction activity of Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) and improve its Na-storage properties.The doped Ti ions not only enlarge the Na migration spacing layer but also improve the structure stability thanks to the strong Ti-O bond.More importantly,the d0-shell electronic structure of Ti^(4+) can suppress the charge transfer from the oxidized anions to cations,thus reducing the anionic redox reaction activity and enhancing the reversibility of charge compensation.The modified Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) cathode shows a reversible capacity of 198 mA h g^(-1) and an increased capacity retention from 15% to 73% after about1 month of cycling.Meanwhile,a superior Na-ion diffusion kinetics and rate capability are also observed.This work advances the commercialization process of Na-based layered iron-manganese oxide cathodes;on the other hand,the proposed modification strategy paves the way for the design of high-performance electrode materials relying on anionic redox reactions.
基金funding support from the Beijing Natural Science Foundation(2252055)National Natural Science Foundation of China(52072033)BIT Research and Innovation Promoting Project(2024YCXY040,GIIP2023-34)。
文摘Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at high voltage.In this work,the strategy of the electron donor was utilized to address this issue.Remarkably,the earth-abundant P2-layered cathode Na_(2/3)Al_(1/6)Fe_(1/6)Mn_(2/3)O_(2)with the presence of K_(2)S renders superior rate capability(187.4 and 79.5 mA h g^(-1)at 20 and 1000 mA g^(-1))and cycling stability(a capacity retention of 85.6% over 300 cycles at 1000 mA g^(-1))within the voltage region of 2-4.4 V Na^(+)/Na.Furthermore,excellent electrochemical performance is also demonstrated in the full cell.Detailed structural analysis of as-proposed composite cathode illustrates that even at 4.4 V irreversible phase transition can be avoided as well as a cell volume variation of only 0.88%,which are attributed to the enhanced performance compared with the control group.Meanwhile,further investigation of charge compensation reveals the crucial role of sulfur ions in actively control of reversible redox reaction of oxygen species in the lattice structure.This work inspires a new strategy to enhance the structural stability of layered sodium ion cathode materials at high voltages.
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Financial supports from the National Natural Science Foundation of China (21822506 and 51761165025)the Tianjin Natural Science Foundation (19JCJQJC62400)the 111 project of B12015。
文摘Anionic redox reaction(ARR) in layered manganese-based oxide cathodes has been considered as an effective strategy to improve the energy density of sodium-ion batteries.Mn-vacancy layered oxides deliver a high ARR-related capacity with small voltage hysteresis,however,they are limited by rapid capacity degradation and poor rate capability,which arise from inferior structure changes due to repeated redox of lattice oxygen.Herein,redox-inactive Ti^(4+)is introduced to substitute partial Mn^(4+)to form Na_(2) Ti_(0.5)Mn_(2.5)O_7(Na_(4/7)[□_(1/7)Ti_(1/7)Mn_(5/7)]O_(2),□ for Mn vacancies),which can effectively restrain unfavorable interlayer gliding of Na2 Mn307 at high charge voltages,as reflected by an ultralow-strain volume variation of 0.11%.There is no irreversible O_(2) evolution observed in Na_(2) Ti_(0.5)Mn_(2.5)O_7 upon charging,which stabilizes the lattice oxygen and ensures the overall structural stability.It exhibits increased capacity retention of 79.1% after 60 cycles in Na_(2) Ti_(0.5)Mn_(2.5)O_7(17.1% in Na_(2) Mn_(3) O_7) and good rate capability(92.1 mAh g^(-1) at 0.5 A g^(-1)).This investigation provides new insights into designing high-performance cathode materials with reversible ARR and structural stability for SIBs.
