高容量镍基O3型层状氧化物高电压下长循环稳定性差的问题严重制约其应用。通过前期研究，申请人提出相转化诱发内应力和表面敏感效应导致各相转化反应界面失效是O3-Na[Ni1-x-yMxNy]O2（M，N为Mn，Co，Ti，Fe其中任何一种元素；x+y<0.5）高电压下循环稳定性差的主要原因。本项目针对这一问题，通过原位XRD，原位拉曼和原位TEM表征技术系统研究高电压下循环过程中诱发内应力和表面敏感效应的变化规律及其对相转化反应界面稳定性的影响机制；提出通过NaTi2(PO4)3表面修饰O3-Na[Ni1-x-yMxNy]O2抑制相转化诱发应力以及表面敏感效应的新策略，阐明NaTi2(PO4)3表面修饰以及表面掺杂对电极高电压下长循环可逆性和稳定性的改善作用；引导开发出容量高和长循环稳定的正极材料，为钠离子电池高容量O3型层状过渡金属氧化物正极材料的基础研究和开发应用提供新思路。

The application of high capacity nickel-based O3 type layered oxide cathodes has been seriously restricted by the poor stability under high voltage for long cycles. Through previous studies, the applicant proposed that the interface failure of the phase transformation reaction due to the phase transformation induced internal stress and surface sensitivity effect is responsible for the poor reversibility of O3-Na[Ni1-x-yMxNy]O2 (M, N is any element of Mn, Co, Ti, Fe; x+y<0.5) under high voltage. In this project, in situ XRD, in situ Raman and in situ TEM characterization techniques were used to systematically study the variation rules of induced internal stress and surface sensitive effect under high voltage for long cycles and its influence mechanism on the interface stability of phase transformation reaction. A novel strategy-NaTi2(PO4)3 surface modified to suppress the phase transformation induced internal stress and surface sensitivity effect, has been proposed. The NaTi2(PO4)3 surface modification and surface doping for the enhancement of long cycles reversibility and cycleability of electrode at high voltage will be elucidated. It guide the development of cathode material with high capacity and long cycleability, and provide new insight for basic research and application of O3-type layer sodium compounds with high capacity for sodium ion batteries.