LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and ...LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and insecurity have hindered their commercial application at scale.In order to overcome these challenges,a kind of tantalum(Ta)doped nickel-rich cathode with reduced size and significantly increased number of primary particles is prepared by combining mechanical fusion with high temperature co-calcination.The elaborately designed micro-morphology of small and uniform primary particles effectively eliminates the local strain accumulation caused by the random orientation of primary particles.Moreover,the uniform distribution of small primary particles stabilizes the spherical secondary particles,thus effectively inhibiting the formation and extension of microcracks.In addition,the formed strong Ta-O bonds restrain the release of lattice oxygen,which greatly increases the structural stability and safety of NCM materials.Therefore,the cathode material with the designed primary particle morphology shows superior electrochemical performance.The 1 mol%Ta-modified cathode(defined as1%Ta-NCM)shows a capacity retention of 97.5%after 200 cycles at 1 C and a rate performance of 137.3 mAh g^(-1)at 5 C.This work presents promising approach to improve the structural stability and safety of nickel-rich NCM.展开更多
Promoting inorganic-rich solid-electrolyte interphase (SEI) formation by constructing anion-rich solvated structures is a promising strategy for improving the long-term cycling of lithium-metal batteries.However,the i...Promoting inorganic-rich solid-electrolyte interphase (SEI) formation by constructing anion-rich solvated structures is a promising strategy for improving the long-term cycling of lithium-metal batteries.However,the increase of anions within the solvated structure inevitably reduces the coordination of Li^(+) with the solvent,which leads to a low lithium diffusion coefficient and a decreased lithium conductivity.Here,high entropy electrolyte is achieved by increasing the molecular diversity in electrolyte.Multiple anions (TFSI^(-),FSI^(-),NO_(3)^(-) and PF_(6)^(-)) presented in entropy electrolyte individually coordinate with Li^(+),creating a diverse and anion-rich solvation structure.The large variety of solvation structures leads to a diversified Li^(+) diffusion barriers in the electrolyte,which results in the increase of channels available for Li^(+) diffusion.Thus,three-dimensional diffusion with high Li^(+) diffusion coefficient occurs in HE electrolytes.Furthermore,the anion-rich solvation structures promote the formation of the inorganic-rich SEI.As a result,over 2000 h of reversible Li plating/stripping with a low overpotential less than 27 mV is achieved in Li||Li cell using electrolyte modified by high-entropy strategy.Besides,the Li||LFP full cell with a negative capacity/positive capacity (N/P) ratio of 4.52 exhibits remarkably enhanced cycling stability,retaining 83.6% of its initial capacity after 150 cycles.This strategy offers a novel approach for accelerating Li^(+) transport kinetics and constructing stable SEI in lithium metal batteries.展开更多
The interfacial chemistry of solid electrolyte interphases(SEI)on lithium(Li)electrode is directly determined by the structural chemistry of the electric double layer(EDL)at the interface.Herein,a strategy for regulat...The interfacial chemistry of solid electrolyte interphases(SEI)on lithium(Li)electrode is directly determined by the structural chemistry of the electric double layer(EDL)at the interface.Herein,a strategy for regulating the structural chemistry of EDL via the introduction of intermolecular hydrogen bonds has been proposed(p-hydroxybenzoic acid(pHA)is selected as proof-of-concept).According to the molecular dynamics(MD)simulation and density functional theory(DFT)calculation results,the existence of hydrogen bonds realizes the anion structural rearrangement in the EDL,reduces the lowest unoccupied molecular orbital(LUMO)energy level of anions in the EDL,and the number of free solvent molecules,which promotes the formation of inorganic species-enriched SEI and eventually achieves the dendrite-free Li deposition.Based on this strategy,Li‖Cu cells can stably run over 185 cycles with an accumulated active Li loss of only 2.27 mAh cm^(-2),and the long-term cycle stability of Li‖Li cells is increased to 1200 h.In addition,the full cell pairing with the commercial LiFePO_(4)(LFP)cathodes exhibits stable cycling performance at 1C,with a capacity retention close to 90%after 200 cycles.展开更多
设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫...设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫化物被证明是锂-氧气电池氧电极反应的有效电催化剂.密度泛函理论计算表明,CuCo_(2)S_(4)/CoS_(1.097)的电子结构在异相界面处受到调控,有利于优化氧电极反应过程中间体的吸附,最终加速氧电极反应动力学.实验结果表明,基于CuCo_(2)S_(4)/CoS_(1.097)的锂-氧气电池在100 m A g^(-1)下具有26,727.8 m A h g^(-1)的高比容量和超过267次循环的出色耐久性.该工作为锂-氧气电池高性能正极材料的设计和构造提供了新视角.展开更多
基金financial support provided by the National Natural Science Foundation of China(52271201)the Science and Technology Department of Sichuan Province(2025NSFTD0005,2022YFG0100,2022ZYD0045)。
文摘LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and insecurity have hindered their commercial application at scale.In order to overcome these challenges,a kind of tantalum(Ta)doped nickel-rich cathode with reduced size and significantly increased number of primary particles is prepared by combining mechanical fusion with high temperature co-calcination.The elaborately designed micro-morphology of small and uniform primary particles effectively eliminates the local strain accumulation caused by the random orientation of primary particles.Moreover,the uniform distribution of small primary particles stabilizes the spherical secondary particles,thus effectively inhibiting the formation and extension of microcracks.In addition,the formed strong Ta-O bonds restrain the release of lattice oxygen,which greatly increases the structural stability and safety of NCM materials.Therefore,the cathode material with the designed primary particle morphology shows superior electrochemical performance.The 1 mol%Ta-modified cathode(defined as1%Ta-NCM)shows a capacity retention of 97.5%after 200 cycles at 1 C and a rate performance of 137.3 mAh g^(-1)at 5 C.This work presents promising approach to improve the structural stability and safety of nickel-rich NCM.
基金supported by the National Natural Science Foundation of China (21905033, 52271201)the Science and Technology Department of Sichuan Province (2022YFG0100,2022ZYD0045)。
文摘Promoting inorganic-rich solid-electrolyte interphase (SEI) formation by constructing anion-rich solvated structures is a promising strategy for improving the long-term cycling of lithium-metal batteries.However,the increase of anions within the solvated structure inevitably reduces the coordination of Li^(+) with the solvent,which leads to a low lithium diffusion coefficient and a decreased lithium conductivity.Here,high entropy electrolyte is achieved by increasing the molecular diversity in electrolyte.Multiple anions (TFSI^(-),FSI^(-),NO_(3)^(-) and PF_(6)^(-)) presented in entropy electrolyte individually coordinate with Li^(+),creating a diverse and anion-rich solvation structure.The large variety of solvation structures leads to a diversified Li^(+) diffusion barriers in the electrolyte,which results in the increase of channels available for Li^(+) diffusion.Thus,three-dimensional diffusion with high Li^(+) diffusion coefficient occurs in HE electrolytes.Furthermore,the anion-rich solvation structures promote the formation of the inorganic-rich SEI.As a result,over 2000 h of reversible Li plating/stripping with a low overpotential less than 27 mV is achieved in Li||Li cell using electrolyte modified by high-entropy strategy.Besides,the Li||LFP full cell with a negative capacity/positive capacity (N/P) ratio of 4.52 exhibits remarkably enhanced cycling stability,retaining 83.6% of its initial capacity after 150 cycles.This strategy offers a novel approach for accelerating Li^(+) transport kinetics and constructing stable SEI in lithium metal batteries.
基金financially supported by the National Natural Science Foundation of China(Grant No.21905033,52271201)the Key Research and DevelopmentProgram of Sichuan Province(Grant No.2022YFG0100)+1 种基金the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(Grant No.2022ZYD0045)the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(Grant No.2020P4FZG02A)
文摘The interfacial chemistry of solid electrolyte interphases(SEI)on lithium(Li)electrode is directly determined by the structural chemistry of the electric double layer(EDL)at the interface.Herein,a strategy for regulating the structural chemistry of EDL via the introduction of intermolecular hydrogen bonds has been proposed(p-hydroxybenzoic acid(pHA)is selected as proof-of-concept).According to the molecular dynamics(MD)simulation and density functional theory(DFT)calculation results,the existence of hydrogen bonds realizes the anion structural rearrangement in the EDL,reduces the lowest unoccupied molecular orbital(LUMO)energy level of anions in the EDL,and the number of free solvent molecules,which promotes the formation of inorganic species-enriched SEI and eventually achieves the dendrite-free Li deposition.Based on this strategy,Li‖Cu cells can stably run over 185 cycles with an accumulated active Li loss of only 2.27 mAh cm^(-2),and the long-term cycle stability of Li‖Li cells is increased to 1200 h.In addition,the full cell pairing with the commercial LiFePO_(4)(LFP)cathodes exhibits stable cycling performance at 1C,with a capacity retention close to 90%after 200 cycles.
基金supported by the National Natural Science Foundation of China(21905033 and 52271201)the Science and Technology Department of Sichuan Province(2022YFG0100)the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(2020P4FZG02A)。
文摘设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫化物被证明是锂-氧气电池氧电极反应的有效电催化剂.密度泛函理论计算表明,CuCo_(2)S_(4)/CoS_(1.097)的电子结构在异相界面处受到调控,有利于优化氧电极反应过程中间体的吸附,最终加速氧电极反应动力学.实验结果表明,基于CuCo_(2)S_(4)/CoS_(1.097)的锂-氧气电池在100 m A g^(-1)下具有26,727.8 m A h g^(-1)的高比容量和超过267次循环的出色耐久性.该工作为锂-氧气电池高性能正极材料的设计和构造提供了新视角.
