The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capac...The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.展开更多
P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phas...P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.展开更多
O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrolla...O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.展开更多
O3-type Na NiO_(2)-based cathode materials undergo irreversible phase transition and serious capacity decay at high voltage above 4.0 V in sodium-ion batteries. To address these challenges, effects of Fsubstitution on...O3-type Na NiO_(2)-based cathode materials undergo irreversible phase transition and serious capacity decay at high voltage above 4.0 V in sodium-ion batteries. To address these challenges, effects of Fsubstitution on the structure and electrochemical performance of Na Ni_(0.4)Mn_(0.25)Ti_(0.3)Co_(0.05)O_(2) are investigated in this article. The F-substitution leads to expanding of interlayer, which can enhance the mobility of Na+. NaNi_(0.4)Mn_(0.25)Ti_(0.3)Co_(0.05)O_(1.92)F_(0.08)(NMTC-F_(0.08)) with the optimal F-substitution degree exhibits much improved rate capability and cyclic stability. It delivers reversible capacities of 177 and 97 m Ah g^(-1) at 0.05 and 5 C within 2.0–4.4 V, respectively. Galvanostatic intermittent titration technique verifies faster kinetics of Na+diffusion in NMTC-F_(0.08). And in-situ XRD investigation reveals the phase evolution of NMTC-F_(0.08), indicating enhanced structural stability results from F-substitution. This study may shed light on the development of high performance cathode materials for sodium-ion storage at high voltage.展开更多
03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hin...03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.展开更多
Sodium-ion batteries(SIBs)have recently gained wildly interest due to the abundance of sodium,lower production costs,and better low-temperature performance compared to lithium-ion batteries(LIBs).Among various cathode...Sodium-ion batteries(SIBs)have recently gained wildly interest due to the abundance of sodium,lower production costs,and better low-temperature performance compared to lithium-ion batteries(LIBs).Among various cathode materials of SIBs,O_(3)-type NaNi_(0.4)Fe_(0.2)Mn_(0.4)O_(2)(NFM424)demonstrates high capacity and ease of synthesis,yet suffers from structural degradation and sluggish Na^(+)kinetics caused by large ionic radius and strong electrostatic interactions.To overcome these issues,a configuration strategy combined with TiO_(2) and Co_(3)O_(4) by a simple solid-state reaction method was introduced to improve structural and electrochemical stability.XRD,SEM,TEM,and various electrochemical characterizations as well as TGA/DSC tests were conducted.The resulting NaNi_(0.4)Fe_(0.2)Mn_(0.3)Co_(0.05)Ti_(0.05)O_(2)(NFMCT)cathode mitigated Jahn-Teller distortions and Na^(+)/vacancy ordering while enhancing phase integrity and diffusion pathways.The obtained NFMCT maintained 93.7 mAh·g^(−1) after 550 cycles at 1 C,with superior rate capabilities at 2 C and 5 C.These findings deepen the understanding of configuration strategy by using multi-element oxide and highlight a practical strategy for designing high-performance SIB cathodes.展开更多
One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stabi...One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.展开更多
Sodium-based O3-type layered oxide materials are attractive for Sodium-ion batteries(SIBs)due to their simple synthesis,affordability,and high capacity.However,challenges remain,including limited reversible capacity a...Sodium-based O3-type layered oxide materials are attractive for Sodium-ion batteries(SIBs)due to their simple synthesis,affordability,and high capacity.However,challenges remain,including limited reversible capacity and poor cycling stability caused by detrimental phase tran-sitions during cycling and the tendency to form sodium carbonate upon air exposure.In this study,based on O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NNFM),a high-entropy strategy was introduced to successfully synthesize O3-type NaNi_(0.25)Fe_(0.21)Mn_(0.18)Co_(0.21)Ti_(0.1)Mg_(0.05)O_(2)(HE-NNFM).The introduction of Co,Ti,and Mg ions increases the system's disorder,highlighting the synergistic interactions among inert atoms.The delayed phase transformation effect in high-entropy materials alleviates the destruction of the O3 structure by the insertion and extraction of sodium ions.Simultaneously,the narrower sodium layer in HE-NNFM acts as a physical barrier,effectively preventing adverse reactions with H2O and CO_(2) in the air,resulting in excellent reversibility and air stability of the HE-NNFM material.Consequently,the HE-NNFM material exhibits a reversible capacity of 110 mAh·g^(-1)with a capacity retention of 97.3%after 200 cycles at 1 C.This work provides insights into the design of high-entropy sodium layered oxides for high-power density storage systems.展开更多
Energy-storage systems and their production have attracted significant interest for practical applications.Batteries are the foundation of sustainable energy sources for electric vehicles(EVs),portable electronic devi...Energy-storage systems and their production have attracted significant interest for practical applications.Batteries are the foundation of sustainable energy sources for electric vehicles(EVs),portable electronic devices(PEDs),etc.In recent decades,Lithium-ion batteries(LIBs) have been extensively utilized in largescale energy storage devices owing to their long cycle life and high energy density.However,the high cost and limited availability of Li are the two main obstacles for LIBs.In this regard,sodium-ion batteries(SIBs) are attractive alternatives to LIBs for large-scale energy storage systems because of the abundance and low cost of sodium materials.Cathode is one of the most important components in the battery,which limits cost and performance of a battery.Among the classified cathode structures,layered structure materials have attracted attention because of their high ionic conductivity,fast diffusion rate,and high specific capacity.Here,we present a comprehensive review of the classification of layered structures and the preparation of layered materials.Furthermore,the review article discusses extensively about the issues of the layered materials,namely(1) electrochemical degradation,(2) irreversible structural changes,and(3) structural instability,and also it provides strategies to overcome the issues such as elemental phase composition,a small amount of elemental doping,structural design,and surface alteration for emerging SIBs.In addition,the article discusses about the recent research development on layered unary,binary,ternary,quaternary,quinary,and senary-based O3-and P2-type cathode materials for high-energy SIBs.This review article provides useful information for the development of high-energy layered sodium transition metal oxide P2 and O3-cathode materials for practical SIBs.展开更多
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X...The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.展开更多
基金financially supported by National Key Research and Development Program of China(No.2022YFE0202400)the National Natural Science Foundation of China(No.22379103)+2 种基金Natural Science Foundation of Guangdong Province of China(No.2021A1515010388)the Science and Technology Projects of Suzhou City(No.SYC2022043)the Qing Lan Project of Jiangsu Province(2022)。
文摘The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.
基金supported by the National Natural Science Foundation of China (22169002)the Chongzuo Key Research and Development Program of China (20220603)the Counterpart Aid Project for Discipline Construction from Guangxi University(2023M02)
文摘P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.
基金supported by the Science and Technology Program of Suzhou(ST202304)the National Natural Science Foundation of China(12275189)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 project。
文摘O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.
基金financial support from the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. NSFC51621001)the Guangdong Special Support Program (2017TQ04N224)+1 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar (Grant No. 2017B030306004)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme。
文摘O3-type Na NiO_(2)-based cathode materials undergo irreversible phase transition and serious capacity decay at high voltage above 4.0 V in sodium-ion batteries. To address these challenges, effects of Fsubstitution on the structure and electrochemical performance of Na Ni_(0.4)Mn_(0.25)Ti_(0.3)Co_(0.05)O_(2) are investigated in this article. The F-substitution leads to expanding of interlayer, which can enhance the mobility of Na+. NaNi_(0.4)Mn_(0.25)Ti_(0.3)Co_(0.05)O_(1.92)F_(0.08)(NMTC-F_(0.08)) with the optimal F-substitution degree exhibits much improved rate capability and cyclic stability. It delivers reversible capacities of 177 and 97 m Ah g^(-1) at 0.05 and 5 C within 2.0–4.4 V, respectively. Galvanostatic intermittent titration technique verifies faster kinetics of Na+diffusion in NMTC-F_(0.08). And in-situ XRD investigation reveals the phase evolution of NMTC-F_(0.08), indicating enhanced structural stability results from F-substitution. This study may shed light on the development of high performance cathode materials for sodium-ion storage at high voltage.
基金supported by the Science and technology plan project of Yulin(2023-CXY-193)the Project funded by Shaanxi Postdoctoral Science Foundation(2023BSHEDZZ274)+2 种基金the Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0588,Z20210201)the Science and technology plan project of Beilin(GX2319)the Science and technology plan project of Ankang(AK2023-GY-08)。
文摘03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.
基金funded by the National Natural Science Foundation of China(Grants 21701083 and 22179054)Jiangsu Provincial Key Research and Development Program(BZ2023010)2023 Jiangsu Government Scholarship for Overseas Studies.
文摘Sodium-ion batteries(SIBs)have recently gained wildly interest due to the abundance of sodium,lower production costs,and better low-temperature performance compared to lithium-ion batteries(LIBs).Among various cathode materials of SIBs,O_(3)-type NaNi_(0.4)Fe_(0.2)Mn_(0.4)O_(2)(NFM424)demonstrates high capacity and ease of synthesis,yet suffers from structural degradation and sluggish Na^(+)kinetics caused by large ionic radius and strong electrostatic interactions.To overcome these issues,a configuration strategy combined with TiO_(2) and Co_(3)O_(4) by a simple solid-state reaction method was introduced to improve structural and electrochemical stability.XRD,SEM,TEM,and various electrochemical characterizations as well as TGA/DSC tests were conducted.The resulting NaNi_(0.4)Fe_(0.2)Mn_(0.3)Co_(0.05)Ti_(0.05)O_(2)(NFMCT)cathode mitigated Jahn-Teller distortions and Na^(+)/vacancy ordering while enhancing phase integrity and diffusion pathways.The obtained NFMCT maintained 93.7 mAh·g^(−1) after 550 cycles at 1 C,with superior rate capabilities at 2 C and 5 C.These findings deepen the understanding of configuration strategy by using multi-element oxide and highlight a practical strategy for designing high-performance SIB cathodes.
基金financially supported by the National Natural Science Foundation of China(Nos.52164029,52074099 and 52464033)Natural Science Foundation of Hainan Province(Nos.221RC585,821MS0782,221MS048 and 221RC 1072)+1 种基金Hainan Province Science and Technology Special Fund(Nos.ZDYF2022GXJS004 and ZDYF2021GXJS028)Scientific Research Foundation of Hainan Tropical Ocean University(No.RHDRC202112)
文摘One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.
基金support from Natural Science Foundation of China(Grant Nos.52371187)the Beijing-Tianjin-Hebei Basic Research Cooperation Special Project(B2024209048)+1 种基金the Central Government Guides Local Science and Technology Development Funds of Hebei Province(226Z4403G)the Ph.D.Research Startup Foundation of North China University of Science and Technology(No.BS2019001).
文摘Sodium-based O3-type layered oxide materials are attractive for Sodium-ion batteries(SIBs)due to their simple synthesis,affordability,and high capacity.However,challenges remain,including limited reversible capacity and poor cycling stability caused by detrimental phase tran-sitions during cycling and the tendency to form sodium carbonate upon air exposure.In this study,based on O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NNFM),a high-entropy strategy was introduced to successfully synthesize O3-type NaNi_(0.25)Fe_(0.21)Mn_(0.18)Co_(0.21)Ti_(0.1)Mg_(0.05)O_(2)(HE-NNFM).The introduction of Co,Ti,and Mg ions increases the system's disorder,highlighting the synergistic interactions among inert atoms.The delayed phase transformation effect in high-entropy materials alleviates the destruction of the O3 structure by the insertion and extraction of sodium ions.Simultaneously,the narrower sodium layer in HE-NNFM acts as a physical barrier,effectively preventing adverse reactions with H2O and CO_(2) in the air,resulting in excellent reversibility and air stability of the HE-NNFM material.Consequently,the HE-NNFM material exhibits a reversible capacity of 110 mAh·g^(-1)with a capacity retention of 97.3%after 200 cycles at 1 C.This work provides insights into the design of high-entropy sodium layered oxides for high-power density storage systems.
基金supported by a grant from the Subway Fine Dust Reduction Technology Development Project of the Ministry of Land Infrastructure and Transport,Republic of Korea(21QPPWB152306-03)the Basic Science Research Capacity Enhancement Project through a Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education of the Republic of Korea(2019R1A6C1010016)。
文摘Energy-storage systems and their production have attracted significant interest for practical applications.Batteries are the foundation of sustainable energy sources for electric vehicles(EVs),portable electronic devices(PEDs),etc.In recent decades,Lithium-ion batteries(LIBs) have been extensively utilized in largescale energy storage devices owing to their long cycle life and high energy density.However,the high cost and limited availability of Li are the two main obstacles for LIBs.In this regard,sodium-ion batteries(SIBs) are attractive alternatives to LIBs for large-scale energy storage systems because of the abundance and low cost of sodium materials.Cathode is one of the most important components in the battery,which limits cost and performance of a battery.Among the classified cathode structures,layered structure materials have attracted attention because of their high ionic conductivity,fast diffusion rate,and high specific capacity.Here,we present a comprehensive review of the classification of layered structures and the preparation of layered materials.Furthermore,the review article discusses extensively about the issues of the layered materials,namely(1) electrochemical degradation,(2) irreversible structural changes,and(3) structural instability,and also it provides strategies to overcome the issues such as elemental phase composition,a small amount of elemental doping,structural design,and surface alteration for emerging SIBs.In addition,the article discusses about the recent research development on layered unary,binary,ternary,quaternary,quinary,and senary-based O3-and P2-type cathode materials for high-energy SIBs.This review article provides useful information for the development of high-energy layered sodium transition metal oxide P2 and O3-cathode materials for practical SIBs.
基金financially supported by (i) Suranaree University of Technology,(ii) Thailand Science Research and Innovation,and (iii) National Science,Research and Innovation Fund(project codes 90464 and 160363)。
文摘The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.
