Lithium-rich layered cathode material(LLM)can meet the requirement of power lithium-ion energy storage devices due to the great energy density.However,the de/intercalation of Li+will cause the irreversible loss of lat...Lithium-rich layered cathode material(LLM)can meet the requirement of power lithium-ion energy storage devices due to the great energy density.However,the de/intercalation of Li+will cause the irreversible loss of lattice oxygen and trigger transition metal(TM)ions migrate to Li+vacancies,resulting in capacity decay.Here we brought Ti4+in substitution of TM ions in Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2),which could stabilize structure and expand the layer spacing of LLM.Moreover,optimized Ti-substitution can regulate the anions and cations of LLM,enhance the interaction with lattice oxygen,increase Ni^(3+) and Co^(3+),and improve Mn^(4+) coordination,improving reversibility of oxygen redox activation,maintaining the stable framework and facilitating the Li^(+) diffusion.Furthermore,we found 5%Ti-substitution sample delivered a high discharge capacity of 244.2 mAh/g at 50 mA/g,an improved cycling stability to 87.3%after 100 cycles and enhanced rate performance.Thereby Ti-substitution gives a new pathway to achieve high reversible cycle retention for LLMs.展开更多
Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elem...Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elements co-exist in the layer(e.g. Ni, Co and Mn). By contrast, the configuration tends to be ordered if the elements are Li and Mn. Here, by using special quasi-random structures(SQS) algorithm, the essential reasons of the ordering in a promising Li-rich Mn-based cathode material Li2MnO3 are investigated. The difference of internal energy and entropy between ordered and disordered materials is calculated. As a result, based on the Gibbs free energy, it is found that Li2MnO3 should have an ordered structure in TM layer. In comparison, structures with Ni-Mn ratio of 2:1 are predicted to have a disordered TM layer, because the entropy terms have larger impact on the structural ordering than internal energy terms.展开更多
Sodium-ion batteries have emerged as promising alternatives to lithium-ion batteries due to their abundant raw material reserves,low cost,enhanced safety,and environmental sustainability.Na_(2)Fe_(2)OS_(2),featuring a...Sodium-ion batteries have emerged as promising alternatives to lithium-ion batteries due to their abundant raw material reserves,low cost,enhanced safety,and environmental sustainability.Na_(2)Fe_(2)OS_(2),featuring a layered anti-perovskite structure,has attracted significant interest for its high capacity and facile synthesis.In this study,density functional theory calculations were performed to systematically investigate the phase stability,ionic conductivity,and voltage characteristics of Na_(2)Fe_(2)OS_(2)as a model system for anti-perovskite layered cathode materials.The compound exhibits excellent phase stability,and its equilibrium potential was calculated for the series Na_(x)Fe_(2)OCh_(2)(0<±<2)(where Ch represents chalcogenides).Naion transport analysis using the climbing image nudged elastic band method reveals a relatively low migration barrier(~0.47eV)along a dingonal pathway,indicating efficient Na^(+)mobility.To expand the materials design space,we systematically explored the effects of substituting Fe with various transition metals and replacing S with Se in NaaTM_(2)OCh_(2)structures.Among the variants studied,Na_(2)Mn_(2)OS_(2) demonstrates the most favorable combination of high voltage(~2.51V),robust phase stability,and superior energy density(~427 W-h/kg).This comprehensive comparison of transition metal substitutions provides vnluable insights for the rational design and experimental development of next-generation anti-perovskite layered cathode materials for sodium-ion batteries.展开更多
Aqueous zinc-ion batteries(ZIBs)have shown great potential in the fields of wearable devices,consumer electronics,and electric vehicles due to their high level of safety,low cost,and multiple electron transfer.The lay...Aqueous zinc-ion batteries(ZIBs)have shown great potential in the fields of wearable devices,consumer electronics,and electric vehicles due to their high level of safety,low cost,and multiple electron transfer.The layered cathode materials of ZIBs hold a stable structure during charge and discharge reactions owing to the ultrafast and straightforward(de)intercalation-type storage mechanism of Zn^(2+)ions in their tunable interlayer spacing and their abilities to accommodate other vip ions or molecules.Nevertheless,the challenges of inadequate energy density,dissolution of active materials,uncontrollable byproducts,increased internal pressure,and a large de-solvation penalty have been deemed an obstacle to the development of ZIBs.In this review,recent strategies on the structure regulation of layered materials for aqueous zinc-ion energy storage devices are systematically summarized.Finally,critical science challenges and future outlooks are proposed to guide and promote the development of advanced cathode materials for ZIBs.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
The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transitio...The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transition caused by the large size difference between Na+and tetrahedral gaps lead to poor rate and cycling performance.Therefore,a scalable and feasible strategy was proposed to modulate local chemical environment by introducing Mg^(2+)and B^(3+)into O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn0.4O_(2),which can distinctly improve kinetic transport rate as well as electrochemical performance.The capacity retention of O_(3)-(Na_(0.82)Mg_(0.04))(Ni_(0.2)Fe_(0.4)Mn_(0.4))B_(0.02)O_(2)(NFMB)increases from 43.3%and 12.4%to 89.5%and 89.0%at 1 C and 3 C after 200 cycles,respectively.Moreover,the electrode still delivers high rate capacity of 93.9 mAh/g when current density increases to 10 C.Mg^(2+)ions riveted on Na layer act as a“pillar”to stabilize crystal structure and inhibit structural change during the desodiumization process.B^(3+)ions entering tetrahedral interstice of the TM layer strengthen the TM-O bond,lower Na+diffusion energy barrier and inhibits the slip of TM layer.Furthermore,the assembled full batteries with the modified cathode material deliver a high energy density of 278.2Wh/kg with commercial hard carbon as anode.This work provides a strategy for the modification of high-performance SIB layered oxide materials to develop the next-generation cost-effective energy storage grid systems.展开更多
To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials an...To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials and optimize Na^(+)diffusion kinetics to ensure high capacity output at various charge-discharge rates.In this research,the targeted F-substitution with a heavy ratio in oxygen anion layer optimizes the Na^(+)diffusion path and electronic conductivity of the material,thereby decreasing the Na^(+)diffusion barrier and imparting high-rate performance.At a 20 C rate,the cathode achieves a capacity of over 80 mAh g^(-1)with stable cycling performance.Additionally,the dual rivet effect between the transition metal layer and oxygen layer prevents significant phase transitions during charge/discharge within the 2-4.2 V range for the modified cathode.As a result,the F-substituted oxygen anion layer improved Na^(+)diffusion,electronic conductivity,and crystal plane structure stability,which led to the development of a highperformance,fast-charging sodium-ion battery(SIB),opening new avenues for commercial applications.展开更多
Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning the...Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.展开更多
Cathode materials Li[CoxNiyMn1-x-y]O2 for lithium secondary batteries have been prepared by a new route using layered double hydroxides （LDHs） as a precursor. The resulting layered phase with the α- NaFe02 structur...Cathode materials Li[CoxNiyMn1-x-y]O2 for lithium secondary batteries have been prepared by a new route using layered double hydroxides （LDHs） as a precursor. The resulting layered phase with the α- NaFe02 structure crystallizes in the rhombohedral system, with space group R-3m having an interlayer spacing close to 0.47 nm. X-ray photoelectron spectroscopy （XPS） was used to measure the oxidation states of Co, Ni and Mn. The effects of varying the Co[Ni[Mn ratio on both the structure and electrochemical properties of Li[CoxNiyMn1-x-y]O2 have been investigated by X-ray diffraction and electrochemical tests. The products demonstrated a rather stable cycling behavior, with a reversible capacity of 118 mAh/g for the layered material with Co/Ni/Mn = 1/1/1.展开更多
O3-NaNi1/3Fe1/3Mn1/3O2is a promising layered cathode material with high specific capacity,low cost,and simple synthesis.However,sluggish kinetic hindrance is attributed to the size discrepancy between the large Na-ion...O3-NaNi1/3Fe1/3Mn1/3O2is a promising layered cathode material with high specific capacity,low cost,and simple synthesis.However,sluggish kinetic hindrance is attributed to the size discrepancy between the large Na-ion and narrow tetrahedral interstitial positions,leading to inferior rate capacity and low reversible capacity.Herein,F with light-weight and strong electronegativity is introduced to substitute O atoms in the bulk structure,which intensifies the bond strength of transition metal and oxygen and enlarges the Na+diffusion channel.In addition,density-functional theory(DFT) calculations demonstrate that the electrostatic interaction is weakened between Na+in the tetrahedral site and the transitionmetal cation directly below it,dramatically reducing the migration barriers of Na+diffusion.Consequently,the as-obtained NaNi1/3Fe1/3Mn1/3O1.95F0.05sample displays outstanding rate performance of 86.7 mA h g^(-1)at 10 C and excellent capacity retention of 84.1% after 100 cycles at 2 C.Moreover,a full cell configuration using a hard carbon anode reaches the energy density of 307.7 Wh kg^(-1).This strategy paves the way for novel means of modulating the Na-ion migration path for high-rate O3-type layered cathode materials.展开更多
To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 was synthesized by a modified co-precipitation method, and the physical and electrochemic...To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li（Ni0.5Co0.2Mn0.3）O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 maintained about 99% after 200 cycles at high temperature（55 ℃）, while that of the bare one was only 86%. Also, unlike bare Li（Ni0.5Co0.2Mn0.3）O2, the Al2O3-modified material cathode exhibited good thermal stability.展开更多
Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structu...Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.展开更多
Layered lithium transition metal oxide(LTMO)cathode materials have attracted much attention for lithium-ion batteries and are shining in the current market.Establishing a clear structure-performance relationship is ne...Layered lithium transition metal oxide(LTMO)cathode materials have attracted much attention for lithium-ion batteries and are shining in the current market.Establishing a clear structure-performance relationship is necessary for the performance improvement of LTMO cathode materials.The combination of synchrotron X-ray diffraction(XRD)with high intensity and XRD Rietveld refinement is powerful for revealing the structural characteristics of LTMO cathode materials.This review summarizes the application of high energy XRD and Rietveld refinement in LTMO cathode materials,including the brief introduction of synchrotron XRD and Rietveld refinement and their applications in understanding the structural evolution related to the synthetic,thermal runaway,cycling,and high-rate charge/discharge process of LTMO cathode materials.Synchrotron XRD can provide insights into the intermediates and reaction paths in the synthesis process,the origin of thermal runaway,the mechanism of structural decay during cycles,and the structural evolution during high-rate charging/discharging.Future works should focus on the development of higher intensity X-rays to gain more in-depth insights into the intrinsic relationship between their structural characteristics and properties.展开更多
Mn-based layered transition metal oxides are promising cathode materials for sodium-ion batteries(SIBs)because of their high theoretical capacities,abundant raw materials,and environment-friendly advantages.However,th...Mn-based layered transition metal oxides are promising cathode materials for sodium-ion batteries(SIBs)because of their high theoretical capacities,abundant raw materials,and environment-friendly advantages.However,they often show insufficient performance due to intrinsic issues including poor structural stability and dissolution of Mn^(3+).Atomic doping is an effective way to address these structural degradation issues.Herein,we reported a new synthesis strategy of a Cu-doped layered cathode by directly calcinating a pure metal-organic framework.Benefiting from the unique structure of MOF with atomic-level Cu doping,a homogeneous Cu-doped layered compound P2-Na_(0.674)Cu_(0.01)Mn_(0.99)O_(2) was obtained.The Cu substitution promotes the crystal structural stability and suppresses the dissolution of Mn,thus preventing the structure degradation of the layered cathode materials.A remarkably enhanced cyclability is realized for the Cu-doped cathode compared with that without Cu doping,with 83.8%capacity retention after 300 cycles at 100 mA·g^(-1).Our findings provide new insights into the design of atomic-level doping layered cathode materials constructed by MOFs for high-performance SIBs.展开更多
Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sampl...Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sample is well-crystallized and has a phase-pure a-NaFeO2 structure. The particle sizes are uniform, and distributed in the range of 20-200 nm. The initial discharge capacity of the Li/LiCo1/3Ni1/3Mn1/3O2 cell was about 149 mAh·g-1 when it was cycled at a voltage range of 4.5-2.3 V with a specific current of 0.25 mA. The result is better in comparison with solid-state solution method. The synthetic procedure was discussed. Three major reactions: chelation, esterification, and polymerization successively occurred.展开更多
This short perspective summarizes recent findings on the role of residual lithium present on the surface of layered Ni-rich oxide cathode materials in liquid-and solid-electrolyte based batteries,with emphasis placed ...This short perspective summarizes recent findings on the role of residual lithium present on the surface of layered Ni-rich oxide cathode materials in liquid-and solid-electrolyte based batteries,with emphasis placed on the carbonate species.Challenges and future research opportunities in the development of carbonate-containing protective nanocoatings for inorganic solid-state battery applications are also discussed.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51972258,22109186).
文摘Lithium-rich layered cathode material(LLM)can meet the requirement of power lithium-ion energy storage devices due to the great energy density.However,the de/intercalation of Li+will cause the irreversible loss of lattice oxygen and trigger transition metal(TM)ions migrate to Li+vacancies,resulting in capacity decay.Here we brought Ti4+in substitution of TM ions in Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2),which could stabilize structure and expand the layer spacing of LLM.Moreover,optimized Ti-substitution can regulate the anions and cations of LLM,enhance the interaction with lattice oxygen,increase Ni^(3+) and Co^(3+),and improve Mn^(4+) coordination,improving reversibility of oxygen redox activation,maintaining the stable framework and facilitating the Li^(+) diffusion.Furthermore,we found 5%Ti-substitution sample delivered a high discharge capacity of 244.2 mAh/g at 50 mA/g,an improved cycling stability to 87.3%after 100 cycles and enhanced rate performance.Thereby Ti-substitution gives a new pathway to achieve high reversible cycle retention for LLMs.
基金Supported by National Key R&D Program of China(2016YFB0700600)Soft Science Research Project of Guangdong Province(No.2017B030301013)
文摘Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elements co-exist in the layer(e.g. Ni, Co and Mn). By contrast, the configuration tends to be ordered if the elements are Li and Mn. Here, by using special quasi-random structures(SQS) algorithm, the essential reasons of the ordering in a promising Li-rich Mn-based cathode material Li2MnO3 are investigated. The difference of internal energy and entropy between ordered and disordered materials is calculated. As a result, based on the Gibbs free energy, it is found that Li2MnO3 should have an ordered structure in TM layer. In comparison, structures with Ni-Mn ratio of 2:1 are predicted to have a disordered TM layer, because the entropy terms have larger impact on the structural ordering than internal energy terms.
基金supported by the National Natural Science Foundation of China(Grant Nos.12404264 and 22209067)Shenzhen Basic Research Program(Natural Science Foundation)Key Project of Basic Research(Grant No.JCYJ20241202123916023)Shenzhen Science and Technology Program(Grant No.KQTD20200820113047086)。
文摘Sodium-ion batteries have emerged as promising alternatives to lithium-ion batteries due to their abundant raw material reserves,low cost,enhanced safety,and environmental sustainability.Na_(2)Fe_(2)OS_(2),featuring a layered anti-perovskite structure,has attracted significant interest for its high capacity and facile synthesis.In this study,density functional theory calculations were performed to systematically investigate the phase stability,ionic conductivity,and voltage characteristics of Na_(2)Fe_(2)OS_(2)as a model system for anti-perovskite layered cathode materials.The compound exhibits excellent phase stability,and its equilibrium potential was calculated for the series Na_(x)Fe_(2)OCh_(2)(0<±<2)(where Ch represents chalcogenides).Naion transport analysis using the climbing image nudged elastic band method reveals a relatively low migration barrier(~0.47eV)along a dingonal pathway,indicating efficient Na^(+)mobility.To expand the materials design space,we systematically explored the effects of substituting Fe with various transition metals and replacing S with Se in NaaTM_(2)OCh_(2)structures.Among the variants studied,Na_(2)Mn_(2)OS_(2) demonstrates the most favorable combination of high voltage(~2.51V),robust phase stability,and superior energy density(~427 W-h/kg).This comprehensive comparison of transition metal substitutions provides vnluable insights for the rational design and experimental development of next-generation anti-perovskite layered cathode materials for sodium-ion batteries.
基金supported by the National Research Foundation(NRF)grants(2022R1A4A1032832 and 2019R1A6A1A10073079)funded by the Korean government(MSIT)
文摘Aqueous zinc-ion batteries(ZIBs)have shown great potential in the fields of wearable devices,consumer electronics,and electric vehicles due to their high level of safety,low cost,and multiple electron transfer.The layered cathode materials of ZIBs hold a stable structure during charge and discharge reactions owing to the ultrafast and straightforward(de)intercalation-type storage mechanism of Zn^(2+)ions in their tunable interlayer spacing and their abilities to accommodate other vip ions or molecules.Nevertheless,the challenges of inadequate energy density,dissolution of active materials,uncontrollable byproducts,increased internal pressure,and a large de-solvation penalty have been deemed an obstacle to the development of ZIBs.In this review,recent strategies on the structure regulation of layered materials for aqueous zinc-ion energy storage devices are systematically summarized.Finally,critical science challenges and future outlooks are proposed to guide and promote the development of advanced cathode materials for ZIBs.
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 National Natural Science Foundation(Nos.52364035,52364036 and U23A20577)Guangxi Natural Science Foundation(Nos.2022GXNSFAA035610 and 2022GXNSFAA035471)Guangxi Science and Technology Base and Talent Project(No.GUIKE AD23026038).
文摘The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transition caused by the large size difference between Na+and tetrahedral gaps lead to poor rate and cycling performance.Therefore,a scalable and feasible strategy was proposed to modulate local chemical environment by introducing Mg^(2+)and B^(3+)into O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn0.4O_(2),which can distinctly improve kinetic transport rate as well as electrochemical performance.The capacity retention of O_(3)-(Na_(0.82)Mg_(0.04))(Ni_(0.2)Fe_(0.4)Mn_(0.4))B_(0.02)O_(2)(NFMB)increases from 43.3%and 12.4%to 89.5%and 89.0%at 1 C and 3 C after 200 cycles,respectively.Moreover,the electrode still delivers high rate capacity of 93.9 mAh/g when current density increases to 10 C.Mg^(2+)ions riveted on Na layer act as a“pillar”to stabilize crystal structure and inhibit structural change during the desodiumization process.B^(3+)ions entering tetrahedral interstice of the TM layer strengthen the TM-O bond,lower Na+diffusion energy barrier and inhibits the slip of TM layer.Furthermore,the assembled full batteries with the modified cathode material deliver a high energy density of 278.2Wh/kg with commercial hard carbon as anode.This work provides a strategy for the modification of high-performance SIB layered oxide materials to develop the next-generation cost-effective energy storage grid systems.
基金supported by the National Natural Science Foundation of China(Nos.22178221,22208221)the Shenzhen Science and Technology Program(Nos.JCYJ20220818095805012,JCYJ20230808105109019)+2 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515011078,2024A1515011507)the Scientific Foundation for Youth Scholars of Shenzhen University(868-000001032522,827-0001004)the Instrumental Analysis Center of Shenzhen University for the assistance with the Electron Microscope technical support。
文摘To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials and optimize Na^(+)diffusion kinetics to ensure high capacity output at various charge-discharge rates.In this research,the targeted F-substitution with a heavy ratio in oxygen anion layer optimizes the Na^(+)diffusion path and electronic conductivity of the material,thereby decreasing the Na^(+)diffusion barrier and imparting high-rate performance.At a 20 C rate,the cathode achieves a capacity of over 80 mAh g^(-1)with stable cycling performance.Additionally,the dual rivet effect between the transition metal layer and oxygen layer prevents significant phase transitions during charge/discharge within the 2-4.2 V range for the modified cathode.As a result,the F-substituted oxygen anion layer improved Na^(+)diffusion,electronic conductivity,and crystal plane structure stability,which led to the development of a highperformance,fast-charging sodium-ion battery(SIB),opening new avenues for commercial applications.
基金the financial support from the National Natural Science Foundation of China(52202338)。
文摘Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.
基金supported by the National Natural Science Foun-dation of China, the 111 Project (grant no.: B07004) the Natural Science Foundation for Young Teachers of Beijing University of Chemical Technology (grant no.: QN0723)
文摘Cathode materials Li[CoxNiyMn1-x-y]O2 for lithium secondary batteries have been prepared by a new route using layered double hydroxides （LDHs） as a precursor. The resulting layered phase with the α- NaFe02 structure crystallizes in the rhombohedral system, with space group R-3m having an interlayer spacing close to 0.47 nm. X-ray photoelectron spectroscopy （XPS） was used to measure the oxidation states of Co, Ni and Mn. The effects of varying the Co[Ni[Mn ratio on both the structure and electrochemical properties of Li[CoxNiyMn1-x-y]O2 have been investigated by X-ray diffraction and electrochemical tests. The products demonstrated a rather stable cycling behavior, with a reversible capacity of 118 mAh/g for the layered material with Co/Ni/Mn = 1/1/1.
基金supported by Shaanxi Province (2023-ZDLGY-24,2023-JC-QN-0588)Xi’an Key Laboratory of Clean Energy(2019219914SYS014CG036)the Open Foundation of State Key Laboratory for Advanced Metals and Materials (2022-Z01)。
文摘O3-NaNi1/3Fe1/3Mn1/3O2is a promising layered cathode material with high specific capacity,low cost,and simple synthesis.However,sluggish kinetic hindrance is attributed to the size discrepancy between the large Na-ion and narrow tetrahedral interstitial positions,leading to inferior rate capacity and low reversible capacity.Herein,F with light-weight and strong electronegativity is introduced to substitute O atoms in the bulk structure,which intensifies the bond strength of transition metal and oxygen and enlarges the Na+diffusion channel.In addition,density-functional theory(DFT) calculations demonstrate that the electrostatic interaction is weakened between Na+in the tetrahedral site and the transitionmetal cation directly below it,dramatically reducing the migration barriers of Na+diffusion.Consequently,the as-obtained NaNi1/3Fe1/3Mn1/3O1.95F0.05sample displays outstanding rate performance of 86.7 mA h g^(-1)at 10 C and excellent capacity retention of 84.1% after 100 cycles at 2 C.Moreover,a full cell configuration using a hard carbon anode reaches the energy density of 307.7 Wh kg^(-1).This strategy paves the way for novel means of modulating the Na-ion migration path for high-rate O3-type layered cathode materials.
基金Funded by the National High Technology Research and Development Program of China(863 Program)(No.2015AA034600)Province Science and Technology in Anhui(No.1301021011)
文摘To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li（Ni0.5Co0.2Mn0.3）O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 maintained about 99% after 200 cycles at high temperature（55 ℃）, while that of the bare one was only 86%. Also, unlike bare Li（Ni0.5Co0.2Mn0.3）O2, the Al2O3-modified material cathode exhibited good thermal stability.
基金National Key R&D Program of China(2022YFB3807700)National Natural Science Foundation of China(22133005,22103093)+4 种基金Science and Technology Commission of Shanghai Municipality(21ZR1472900,22ZR1471600,23ZR1472600)Youth Innovation Promotion Association CAS(2022251)Shanghai Super Post-Doctor Incentive Program(2022665)China Postdoctoral Science Foundation(2023M733621)Shanghai Explorer Program(Batch I)(23TS1401500)。
文摘Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.
基金This work was supported by the National Natural Science Foundation of China(Nos.22121005,22020102002,and 21835004)the Frontiers Science Center for New Organic Matter of Nankai University(No.63181206).
文摘Layered lithium transition metal oxide(LTMO)cathode materials have attracted much attention for lithium-ion batteries and are shining in the current market.Establishing a clear structure-performance relationship is necessary for the performance improvement of LTMO cathode materials.The combination of synchrotron X-ray diffraction(XRD)with high intensity and XRD Rietveld refinement is powerful for revealing the structural characteristics of LTMO cathode materials.This review summarizes the application of high energy XRD and Rietveld refinement in LTMO cathode materials,including the brief introduction of synchrotron XRD and Rietveld refinement and their applications in understanding the structural evolution related to the synthetic,thermal runaway,cycling,and high-rate charge/discharge process of LTMO cathode materials.Synchrotron XRD can provide insights into the intermediates and reaction paths in the synthesis process,the origin of thermal runaway,the mechanism of structural decay during cycles,and the structural evolution during high-rate charging/discharging.Future works should focus on the development of higher intensity X-rays to gain more in-depth insights into the intrinsic relationship between their structural characteristics and properties.
基金This work was supported by the National Key Research and Development Program of China(2019YFE0118800).
文摘Mn-based layered transition metal oxides are promising cathode materials for sodium-ion batteries(SIBs)because of their high theoretical capacities,abundant raw materials,and environment-friendly advantages.However,they often show insufficient performance due to intrinsic issues including poor structural stability and dissolution of Mn^(3+).Atomic doping is an effective way to address these structural degradation issues.Herein,we reported a new synthesis strategy of a Cu-doped layered cathode by directly calcinating a pure metal-organic framework.Benefiting from the unique structure of MOF with atomic-level Cu doping,a homogeneous Cu-doped layered compound P2-Na_(0.674)Cu_(0.01)Mn_(0.99)O_(2) was obtained.The Cu substitution promotes the crystal structural stability and suppresses the dissolution of Mn,thus preventing the structure degradation of the layered cathode materials.A remarkably enhanced cyclability is realized for the Cu-doped cathode compared with that without Cu doping,with 83.8%capacity retention after 300 cycles at 100 mA·g^(-1).Our findings provide new insights into the design of atomic-level doping layered cathode materials constructed by MOFs for high-performance SIBs.
文摘Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sample is well-crystallized and has a phase-pure a-NaFeO2 structure. The particle sizes are uniform, and distributed in the range of 20-200 nm. The initial discharge capacity of the Li/LiCo1/3Ni1/3Mn1/3O2 cell was about 149 mAh·g-1 when it was cycled at a voltage range of 4.5-2.3 V with a specific current of 0.25 mA. The result is better in comparison with solid-state solution method. The synthetic procedure was discussed. Three major reactions: chelation, esterification, and polymerization successively occurred.
基金F Strauss acknowledges financial support from the Fonds der Chemischen Industrie(FCI)through a Liebig fellowship.This work was partially supported by BASF SE.
文摘This short perspective summarizes recent findings on the role of residual lithium present on the surface of layered Ni-rich oxide cathode materials in liquid-and solid-electrolyte based batteries,with emphasis placed on the carbonate species.Challenges and future research opportunities in the development of carbonate-containing protective nanocoatings for inorganic solid-state battery applications are also discussed.
