The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and qu...The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and quick diffusion of sodium ions to fulfill the requirements for efficient and ecofriendly energy storage systems.In this vein,density functional theory(DFT)calculation has become instrumental in advancing the study of battery materials.This study presents a firstprinciples investigation of P2-type Na_(x)NiO_(2)and Na_(x)Ni_(0.75)M_(0.25)O_(2)(M=Cu,Fe,Mn)cathode materials for sodium-ion batteries(SIBs),focusing on Na content variation and its impact on the battery performance.For NaNiO_(2),we replaced part of the expensive Ni element with lower-cost Cu,Fe,and Mn in hopes of reducing costs and improving material performance.By employing density functional theory(DFT),we explore the relationship between lattice constants,cell volume,enthalpy of formation,and cell voltage,and how these factors influence sodium ion insertion/extraction.We provide insights into the diffusion paths and activation energies for Na ions,and assess the influence of transition metal(TM)substitution on the structural stability and electrochemical properties of the materials.Additionally,the study delves into the electronic structure,highlighting how Cu and Fe integration refines the band gap of the spin-down bands.The findings reveal that certain transition metal substitutions can enhance performance,offering a pathway to optimize sodium-ion battery electrode materials.展开更多
The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues dem...The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues demonstrated that high Na-content P2-type layered oxides exhibit higher capacities as well as great structural stability.展开更多
Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during ins...Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.展开更多
Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high ener...Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material.The combined analysis of ex-situ X-ray absorption fine structure(XAFS)spectroscopy,aberration-corrected high resolution transmission electron microscopy(AB-HRTEM)and X-ray diffraction(XRD)show that the strong Ti–O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2)exhibits a reversible capacity of 89.6 mA h g^(-1)even at 5 C,an excellent cyclability with 88.78%capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.展开更多
The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate per...The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.展开更多
P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale ...P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.展开更多
The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a sol...The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a solid-state route.The effect of La3+substitution was researched as high-rate SIBs cathode.The Na0.67Co0.35Ti0.20Mn0.44La0.01O2 exhibits a superior initial specific capacity of 162.7 and 125.9 mA h/g after50 cycles at 0.1 C rate,and the initial specific discharge capacity of 115.2 mA h/g with 60.6%capacity retention after 100 cycles at 1 C In addition,the Na0.67Co0.35Ti0.20Mn0.44La0.01O2 sample shows an excellent rate capacity of 91.9 and 60.4 mA·h/g with 46.9%and 50.9%capacity retentions even at 8 C and 10 C rate after100 cycles,respectively.The promising La-substituted P2-type Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 material provides a new strategy for designing high-rate performance of SIBs.展开更多
The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the a...The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the anionic reaction of O^(2-)/O~-to occur during Na^(+) de/intercalation.However,here,we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru^(4+)/Ru^(5+).Combining studies using first-principles calculation and experimental techniques reveals that further Na^(+) deintercalation from P2-Na_(0.33)[Mg_(0.33)Ru_(0.67)]O_(2) is based on anionic oxidation after 0.33 mol Na^(+) deintercalation from P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) with cationic oxidation of Ru^(4+)/Ru^(4.5+).Especially,it is revealed that the only oxygen neighboring 2Mg/1 Ru can participate in the anionic redox during Na^(+) de/intercalation,which implies that the Na-O-Mg arrangement in the P2-Na_(0.33)[M9_(0.33)Ru_(0.67)]O_(2) structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox.Through the O anionic and Ru cationic reaction,P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) exhibits not only a large specific capacity of~172 mA h g^(-1) but also excellent power-capability via facile Na^(+) diffusion and reversible structural change during charge/discharge.These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.展开更多
P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirabl...P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirable electrochemical performances by inducing anion/cation ions,changing morphology,adjusting valence,etc.In this work,several same-period elements of Sc,Ti,V,Cr,Fe,Cu and Zn are doped into Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)O_(2)cathodes,which are manipulated by ions radii and valence state,further studied by operando X-ray powder diffraction patterns(XRD).As a result,the Cu^(2+)doped cathode performed higher rate capacities(as high as 86 mAh/g even at 10 C)and more stable structures(capacity retention of~89.4%for 100 cycles),which owing to the synergistic effect among the tightened TMO_(2)layer,enlarged d-spacing,reduce O-O electrostatic repulsion,ameliorate lattice distortion as well as mitigate ordering of Na^(+)/vacancy.展开更多
The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much attention.However,determining how to tune the anionic redox reaction is still a major challenge.Herein,we tune the activi...The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much attention.However,determining how to tune the anionic redox reaction is still a major challenge.Herein,we tune the activity and reversibility of both the anionic and cationic redox reactions of Na0.67Mn0.5Fe0.5O2 though an integrated strategy that combines the advantages of Li2SiO3 coating,Li doping and Si doping,and the initial capacity,rate performance and cycling stability are significantly improved.The in-depth modulation mechanism is revealed by means of neutron diffraction,X-ray absorption spectroscopy,in situ X-ray diffraction,electron paramagnetic resonance spectroscopy,first-principles calculations and so on.The Li2SiO3 coating alleviates the side reactions and enhances the cycling stability.Si^4+doping lowers the Na^+diffusion barrier due to the expanded interlayer spacing.Additionally,Si^4+doping improves the structural stability,oxygen redox activity and reversibility.Li^+doping in Na sites further increases the structure stability.The electron density maps confirm the greater activity of Na and O in the modified sample.Nuclear density maps and bond-valence energy landscapes identify the Na^+migration pathway from Nae site to Naf site(the positions of the Na ions in the crystal structure).The proposed insights into the modulation mechanism of the anionic and cationic redox chemistry are also instructive for designing other oxide-based cathode materials.展开更多
To power large-scale energy storage systems,sodium-ion batteries(SIBs)must have not only high-energy density but also high performance under a low-temperature(LT)environment.P2-type manganese oxides with high specific...To power large-scale energy storage systems,sodium-ion batteries(SIBs)must have not only high-energy density but also high performance under a low-temperature(LT)environment.P2-type manganese oxides with high specific capacity are promising cathode candidates for SIBs,but their LT applications are limitedly explored.We proposed a P2-type Na_(0.67)Ni_(0.1)Co_(0.1)Mn_(0.8)O_(2) material with outstanding LT performance prepared through reasonable structure modulation.The material offers an excellent Na^(+) diffusion coefficient(approximately 10^(−9)-10^(−7.5) cm^(2) s^(−1))at−20℃,a superior LT discharge capacity of 147.4 mA h g^(−1) in the Na half-cell system,and outstanding LT full cell performance(energy density of 358.3 W h kg^(−1)).Various characterisations and density function theory calculations results show that the solid solution reaction and pseudocapacitive feature promote the diffusion and desolvation of Na+from the bulk electrode to interface,finally achieving superior electrochemical performance at LT.展开更多
P2-type layered oxides with the general Na-deficient composition Na_(x)TMO_(2)(x<1,TM:transition metal)are a promising class of cathode materials for sodium-ion batteries.The open Na+transport pathways present in t...P2-type layered oxides with the general Na-deficient composition Na_(x)TMO_(2)(x<1,TM:transition metal)are a promising class of cathode materials for sodium-ion batteries.The open Na+transport pathways present in the structure lead to low diffusion barriers and enable high charge/discharge rates.However,a phase transition from P2 to O2 structure occurring above 4.2 V and metal dissolution at low potentials upon discharge results in rapid capacity degradation.In this work,we demonstrate the positive effect of configurational entropy on the stability of the crystal structure during battery operation.Three different compositions of layered P2-type oxides were synthesized by solid-state chemistry,Na_(0.67)(Mn_(0.55)Ni_(0.21)Co_(0.24))O_(2),Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.24)Ti_(0.1)Mg_(0.03))O_(2) and Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.18)Ti_(0.1)Mg_(0.03)Al_(0.04)Fe_(0.02))O_(2) with low,medium and high configurational entropy,respectively.The high-entropy cathode material shows lower structural transformation and Mn dissolution upon cycling in a wide voltage range from 1.5 to 4.6 V.Advanced operando techniques and post-mortem analysis were used to probe the underlying reaction mechanism thoroughly.Overall,the high-entropy strategy is a promising route for improving the electrochemical performance of P2 layered oxide cathodes for advanced sodium-ion battery applications.展开更多
Layered P2-type cathodes with high voltage,large capacity,and easy synthesis show great potential for developing sodium(Na)-ion batteries(NIBs).However,the P2–O2 phase transition makes their structural degradation an...Layered P2-type cathodes with high voltage,large capacity,and easy synthesis show great potential for developing sodium(Na)-ion batteries(NIBs).However,the P2–O2 phase transition makes their structural degradation and the Na^(+)/vacancy ordering lowers their redox kinetics.Here,we rationally propose a compositionally graded P2-type cathode,where nickel(Ni)and manganese(Mn)fractions decrease gradually,and cobalt(Co)content increases contiguously from the inside to the outside of a secondary particle.Inside these particles,the Ni/Mn-based compound delivers high capacity and high voltage.On the surface of particles,the Co/Mn-based solid solution offers a stable buffer matrix.Benefiting from these synergistic effects,this graded P2-type cathode shows the elimination of P2–O2 transformation even when charged to 4.4 V,which enables good structural stability,maintaining capacity retention reaching~80%within 300 cycles.Moreover,the Na^(+)/vacancy ordering superstructure is further suppressed,and the Na^(+)diffusion kinetics is significantly improved.The proposed graded structure with optimized chemical composition offers a new perspective for eliminating the unwanted phase transition and thus enhancing the electrochemistry of high-voltage layered cathodes for advanced NIBs.展开更多
P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition...P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition induced by the O^(2-)−O^(2-)−electrostatic repulsion upon high-voltage charge,which leads to rapid capacity fade.Herein,we construct a P2-type Ni–Mn-based layered oxide cathode with a core-shell structure(labeled as NM–Mg–CS).The P2-Na_(0.67)[Ni_(0.25)Mn_(0.75)]O_(2)(NM)core is enclosed by the robust P2-Na_(0.67)[Ni_(0.21)Mn_(0.71)Mg_(0.08)]O_(2)(NM–Mg)shell.The NM–Mg–CS exhibits the phase-transition-free character with mitigated volume change because the confinement effect of shell is conductive to inhibit the irreversible phase transition of the core material.As a result,it drives a high capacity retention of 81%after 1000 cycles at 5 C with an initial capacity of 78mA h/g.And the full cell with the NM–Mg–CS cathode and hard carbon anode delivers stable capacities over 250 cycles.The successful construction of the core-shell structure in P2-type layered oxides sheds light on the development of high-capacity and long-life cathode materials for 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
基金the financial support from the National Natural Science Foundation of China(No.52072379)the Recruitment Program of Global Experts,and the Fundamental Research Funds for the Central Universities(WK2060000016)。
文摘The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and quick diffusion of sodium ions to fulfill the requirements for efficient and ecofriendly energy storage systems.In this vein,density functional theory(DFT)calculation has become instrumental in advancing the study of battery materials.This study presents a firstprinciples investigation of P2-type Na_(x)NiO_(2)and Na_(x)Ni_(0.75)M_(0.25)O_(2)(M=Cu,Fe,Mn)cathode materials for sodium-ion batteries(SIBs),focusing on Na content variation and its impact on the battery performance.For NaNiO_(2),we replaced part of the expensive Ni element with lower-cost Cu,Fe,and Mn in hopes of reducing costs and improving material performance.By employing density functional theory(DFT),we explore the relationship between lattice constants,cell volume,enthalpy of formation,and cell voltage,and how these factors influence sodium ion insertion/extraction.We provide insights into the diffusion paths and activation energies for Na ions,and assess the influence of transition metal(TM)substitution on the structural stability and electrochemical properties of the materials.Additionally,the study delves into the electronic structure,highlighting how Cu and Fe integration refines the band gap of the spin-down bands.The findings reveal that certain transition metal substitutions can enhance performance,offering a pathway to optimize sodium-ion battery electrode materials.
文摘The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues demonstrated that high Na-content P2-type layered oxides exhibit higher capacities as well as great structural stability.
基金financially supported by the National Natural Science Foundation of China(Nos.52372188,51902090)Henan Key Research Project Plan for Higher Education Institutions(No.23A150038)+6 种基金2023 Introduction of Studying Abroad Talent Program“111”Project(No.D17007)Henan Provincial Key Scientific Research Project of Colleges and Universities(No23A150038)Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National Students’Platform for Innovation and Entrepreneurship Training Program(No.201910476010)the China Postdoctoral Science Foundation(No.2019 M652546)the Henan Province Postdoctoral StartUp Foundation(No.1901017)。
文摘Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.
基金the National Natural Science Foundation of China(No.11705015,U1832147)the Science and Technology Plan Project of Suzhou(Nos.SYG201738 and SZS201710)。
文摘Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material.The combined analysis of ex-situ X-ray absorption fine structure(XAFS)spectroscopy,aberration-corrected high resolution transmission electron microscopy(AB-HRTEM)and X-ray diffraction(XRD)show that the strong Ti–O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2)exhibits a reversible capacity of 89.6 mA h g^(-1)even at 5 C,an excellent cyclability with 88.78%capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.
基金financially supported by the Australian Research Council(ARC) through the Future Fellowship(FT180100705)the financial support from China Scholarship Council+3 种基金the support from UTS-HUST Key Technology Partner Seed Fundthe support from Open Project of State Key Laboratory of Advanced Special Steel,the Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2021-04)the Science and Technology Commission of Shanghai Municipality(22010500400)“Joint International Laboratory on Environmental and Energy Frontier Materials”and“Innovation Research Team of High–Level Local Universities in Shanghai”in Shanghai University。
文摘The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12105372 and 51991344)President's Foundation of China Institute of Atomic Energy(Grant No.16YZ202212000201)Chinese Academy of Sciences(Grant No.XDB33000000).
文摘P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.
文摘The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a solid-state route.The effect of La3+substitution was researched as high-rate SIBs cathode.The Na0.67Co0.35Ti0.20Mn0.44La0.01O2 exhibits a superior initial specific capacity of 162.7 and 125.9 mA h/g after50 cycles at 0.1 C rate,and the initial specific discharge capacity of 115.2 mA h/g with 60.6%capacity retention after 100 cycles at 1 C In addition,the Na0.67Co0.35Ti0.20Mn0.44La0.01O2 sample shows an excellent rate capacity of 91.9 and 60.4 mA·h/g with 46.9%and 50.9%capacity retentions even at 8 C and 10 C rate after100 cycles,respectively.The promising La-substituted P2-type Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 material provides a new strategy for designing high-rate performance of SIBs.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2021R1A2C1014280)supported by the “Regional Innovation Strategy (RIS)” through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2021RIS-004)+1 种基金the Fundamental Research Program of the Korea Institute of Material Science (KIMS) (PNK9370)the calculation resources were supported by the Supercomputing Center in Korea Institute of Science and Technology Information (KISTI) (KSC-2022-CRE-0030)。
文摘The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the anionic reaction of O^(2-)/O~-to occur during Na^(+) de/intercalation.However,here,we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru^(4+)/Ru^(5+).Combining studies using first-principles calculation and experimental techniques reveals that further Na^(+) deintercalation from P2-Na_(0.33)[Mg_(0.33)Ru_(0.67)]O_(2) is based on anionic oxidation after 0.33 mol Na^(+) deintercalation from P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) with cationic oxidation of Ru^(4+)/Ru^(4.5+).Especially,it is revealed that the only oxygen neighboring 2Mg/1 Ru can participate in the anionic redox during Na^(+) de/intercalation,which implies that the Na-O-Mg arrangement in the P2-Na_(0.33)[M9_(0.33)Ru_(0.67)]O_(2) structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox.Through the O anionic and Ru cationic reaction,P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) exhibits not only a large specific capacity of~172 mA h g^(-1) but also excellent power-capability via facile Na^(+) diffusion and reversible structural change during charge/discharge.These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.
基金financially supported by the National Natural Science Foundation of China(Nos.52263010,51902090)Henan Key Research Project Plan for Higher Education Institutions(No.23A150038)+5 种基金2023 Introduction of studying abroad talent program,“"111"Project(No.D17007)Henan Provincial Key Scientific Research Project of Colleges and Universities(No.23A150038)Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National students'platform for innovation and entrepreneurship training program(No.201910476010)the China Postdoctoral Science Foundation(No.2019 M652546)the Henan Province Postdoctoral Start-Up Foundation(No.1901017).
文摘P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirable electrochemical performances by inducing anion/cation ions,changing morphology,adjusting valence,etc.In this work,several same-period elements of Sc,Ti,V,Cr,Fe,Cu and Zn are doped into Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)O_(2)cathodes,which are manipulated by ions radii and valence state,further studied by operando X-ray powder diffraction patterns(XRD).As a result,the Cu^(2+)doped cathode performed higher rate capacities(as high as 86 mAh/g even at 10 C)and more stable structures(capacity retention of~89.4%for 100 cycles),which owing to the synergistic effect among the tightened TMO_(2)layer,enlarged d-spacing,reduce O-O electrostatic repulsion,ameliorate lattice distortion as well as mitigate ordering of Na^(+)/vacancy.
基金supported by the National Natural Science Foundation of China(11975238 and 11575192)the Scientific Instrument Developing Project(ZDKYYQ20170001)+3 种基金the International Partnership Program(211211KYSB20170060 and 211211KYSB20180020)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB28000000)the Natural Science Foundation of Beijing Municipality(2182082)The support from University of Chinese Academy of Sciences is also appreciated。
文摘The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much attention.However,determining how to tune the anionic redox reaction is still a major challenge.Herein,we tune the activity and reversibility of both the anionic and cationic redox reactions of Na0.67Mn0.5Fe0.5O2 though an integrated strategy that combines the advantages of Li2SiO3 coating,Li doping and Si doping,and the initial capacity,rate performance and cycling stability are significantly improved.The in-depth modulation mechanism is revealed by means of neutron diffraction,X-ray absorption spectroscopy,in situ X-ray diffraction,electron paramagnetic resonance spectroscopy,first-principles calculations and so on.The Li2SiO3 coating alleviates the side reactions and enhances the cycling stability.Si^4+doping lowers the Na^+diffusion barrier due to the expanded interlayer spacing.Additionally,Si^4+doping improves the structural stability,oxygen redox activity and reversibility.Li^+doping in Na sites further increases the structure stability.The electron density maps confirm the greater activity of Na and O in the modified sample.Nuclear density maps and bond-valence energy landscapes identify the Na^+migration pathway from Nae site to Naf site(the positions of the Na ions in the crystal structure).The proposed insights into the modulation mechanism of the anionic and cationic redox chemistry are also instructive for designing other oxide-based cathode materials.
基金the financial support from the National Natural Science Foundation of China(51774251)Shanghai Science and Technology Commission’s"2020 Science and Technology Innovation Action Plan"(20511104003)+2 种基金the Natural Science Foundation of Shanghai(21ZR1424200)Hebei Natural Science Foundation for Distinguished Young Scholars(B2017203313)Talent Engineering Training Funds of Hebei Province(A201802001)。
文摘To power large-scale energy storage systems,sodium-ion batteries(SIBs)must have not only high-energy density but also high performance under a low-temperature(LT)environment.P2-type manganese oxides with high specific capacity are promising cathode candidates for SIBs,but their LT applications are limitedly explored.We proposed a P2-type Na_(0.67)Ni_(0.1)Co_(0.1)Mn_(0.8)O_(2) material with outstanding LT performance prepared through reasonable structure modulation.The material offers an excellent Na^(+) diffusion coefficient(approximately 10^(−9)-10^(−7.5) cm^(2) s^(−1))at−20℃,a superior LT discharge capacity of 147.4 mA h g^(−1) in the Na half-cell system,and outstanding LT full cell performance(energy density of 358.3 W h kg^(−1)).Various characterisations and density function theory calculations results show that the solid solution reaction and pseudocapacitive feature promote the diffusion and desolvation of Na+from the bulk electrode to interface,finally achieving superior electrochemical performance at LT.
基金financial support from the China Scholarship Council(CSC)financial support by Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy,EXC 2154,project number 390874152+8 种基金financial support from the Federal Ministry of Education and Research(Bundesministerium für Bildung und Forschung,BMBF)under the project‘KaSiLi’(03XP0254D)in the competence cluster‘Excell-BattMat’financial support from the Helmholtz Association(DigiBat project)support by the German Research Foundation(to H H,Grant No.HA 1344/43-1)is gratefully acknowledgedsupport from EnABLES and EPISTORE,projects funded by the European Union’s Horizon 2020 research and innovation program under Grant Agreement No.730957 and 101017709,respectivelyfunding from the Kera-Solar project(Carl Zeiss Foundation)support at beamline P65 of the PETRA Ⅲ synchrotron(Deutsches Elektronen-Synchrotron DESY,Hamburg,Germany)is gratefully acknowledgedEduard Arzt(INM)for his continuing supportAndrea Jung(INM)for her support on ICP-OES measurementsthe support from the Karlsruhe Nano Micro Facility(KNMF,www.knmf.kit.edu),a Helmholtz research infrastructure at Karlsruhe Institute of Technology(KIT,www.kit.du).
文摘P2-type layered oxides with the general Na-deficient composition Na_(x)TMO_(2)(x<1,TM:transition metal)are a promising class of cathode materials for sodium-ion batteries.The open Na+transport pathways present in the structure lead to low diffusion barriers and enable high charge/discharge rates.However,a phase transition from P2 to O2 structure occurring above 4.2 V and metal dissolution at low potentials upon discharge results in rapid capacity degradation.In this work,we demonstrate the positive effect of configurational entropy on the stability of the crystal structure during battery operation.Three different compositions of layered P2-type oxides were synthesized by solid-state chemistry,Na_(0.67)(Mn_(0.55)Ni_(0.21)Co_(0.24))O_(2),Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.24)Ti_(0.1)Mg_(0.03))O_(2) and Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.18)Ti_(0.1)Mg_(0.03)Al_(0.04)Fe_(0.02))O_(2) with low,medium and high configurational entropy,respectively.The high-entropy cathode material shows lower structural transformation and Mn dissolution upon cycling in a wide voltage range from 1.5 to 4.6 V.Advanced operando techniques and post-mortem analysis were used to probe the underlying reaction mechanism thoroughly.Overall,the high-entropy strategy is a promising route for improving the electrochemical performance of P2 layered oxide cathodes for advanced sodium-ion battery applications.
基金funded by the National Natural Science Foundation of China(No.52102252)the Natural Science Foundation of Shandong Province(No.ZR2021QB052)China Postdoctoral Science Foundation(No.2021T140268).
文摘Layered P2-type cathodes with high voltage,large capacity,and easy synthesis show great potential for developing sodium(Na)-ion batteries(NIBs).However,the P2–O2 phase transition makes their structural degradation and the Na^(+)/vacancy ordering lowers their redox kinetics.Here,we rationally propose a compositionally graded P2-type cathode,where nickel(Ni)and manganese(Mn)fractions decrease gradually,and cobalt(Co)content increases contiguously from the inside to the outside of a secondary particle.Inside these particles,the Ni/Mn-based compound delivers high capacity and high voltage.On the surface of particles,the Co/Mn-based solid solution offers a stable buffer matrix.Benefiting from these synergistic effects,this graded P2-type cathode shows the elimination of P2–O2 transformation even when charged to 4.4 V,which enables good structural stability,maintaining capacity retention reaching~80%within 300 cycles.Moreover,the Na^(+)/vacancy ordering superstructure is further suppressed,and the Na^(+)diffusion kinetics is significantly improved.The proposed graded structure with optimized chemical composition offers a new perspective for eliminating the unwanted phase transition and thus enhancing the electrochemistry of high-voltage layered cathodes for advanced NIBs.
基金supported by the National Natural Science Foundation of China(Nos.22121005 and 52072186)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(No.JDSX2023003)+1 种基金the National Key Research and Development Program of China(Nos.2022YFB2402200 and 2019YFA0705600)the Fundamental Research Funds for the Central Universities of China(Nos.63233017,63231002,and 63231198).
文摘P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition induced by the O^(2-)−O^(2-)−electrostatic repulsion upon high-voltage charge,which leads to rapid capacity fade.Herein,we construct a P2-type Ni–Mn-based layered oxide cathode with a core-shell structure(labeled as NM–Mg–CS).The P2-Na_(0.67)[Ni_(0.25)Mn_(0.75)]O_(2)(NM)core is enclosed by the robust P2-Na_(0.67)[Ni_(0.21)Mn_(0.71)Mg_(0.08)]O_(2)(NM–Mg)shell.The NM–Mg–CS exhibits the phase-transition-free character with mitigated volume change because the confinement effect of shell is conductive to inhibit the irreversible phase transition of the core material.As a result,it drives a high capacity retention of 81%after 1000 cycles at 5 C with an initial capacity of 78mA h/g.And the full cell with the NM–Mg–CS cathode and hard carbon anode delivers stable capacities over 250 cycles.The successful construction of the core-shell structure in P2-type layered oxides sheds light on the development of high-capacity and long-life cathode materials for 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.
