The irreversible anionic redox reaction and oxygen release of Li-rich layered oxide cathodes seriously hinder their commercial application.Here,a synergistic modification strategy of surface dielectric coating(TiNb_(2...The irreversible anionic redox reaction and oxygen release of Li-rich layered oxide cathodes seriously hinder their commercial application.Here,a synergistic modification strategy of surface dielectric coating(TiNb_(2)O_(7))and bulk phase Ti doping is proposed in this paper.TiNb_(2)O_(7),as a dielectric oxide,can generate a reversed electric field during charging to block the migration path of anions inside the material.In addition,the unique three-dimensional Li+diffusion channels of TiNb_(2)O_(7)can improve the lithium-ion diffusion kinetics.The results show that the synergistic modification strategy fundamentally inhibits oxygen loss and enhances the reversibility of anion redox,while constructing a uniform and stable CEI interface.The co-modification strategy effectively improves the electrochemical performance of the materials.The modified sample can maintain a high capacity of 175.1 mA h g^(−1)after 500 cycles at 1 C.This work provides new insights to improve the oxygen loss problem of Li-rich layered oxide cathodes.展开更多
基金supported by the National Natural Science Foundation of China(51972023).
文摘The irreversible anionic redox reaction and oxygen release of Li-rich layered oxide cathodes seriously hinder their commercial application.Here,a synergistic modification strategy of surface dielectric coating(TiNb_(2)O_(7))and bulk phase Ti doping is proposed in this paper.TiNb_(2)O_(7),as a dielectric oxide,can generate a reversed electric field during charging to block the migration path of anions inside the material.In addition,the unique three-dimensional Li+diffusion channels of TiNb_(2)O_(7)can improve the lithium-ion diffusion kinetics.The results show that the synergistic modification strategy fundamentally inhibits oxygen loss and enhances the reversibility of anion redox,while constructing a uniform and stable CEI interface.The co-modification strategy effectively improves the electrochemical performance of the materials.The modified sample can maintain a high capacity of 175.1 mA h g^(−1)after 500 cycles at 1 C.This work provides new insights to improve the oxygen loss problem of Li-rich layered oxide cathodes.
