As a cathode material for lithium-ion batteries with the highest capacity (>280 mAh g⁻¹) in the intercalated lithium storage mode, lithium-rich layered oxides still suffer from capacity decay, voltage attenuation and hysteresis caused by the unstable O evolution. In this work, Os surface doping has been applied to Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ for structural dimension gradient design of oxygen framework, inducing a surface heterostructure with three-dimensional Li/transition metal (TM) cations disorder. The octahedral coordination environment of surface oxygen transforms into a random and disordered distribution of Li/TM, differing from the two-dimensional ordered oxygen framework configuration inside the bulk. This promotes the three-dimensional disordered arrangement of O 2p unhybridized orbitals, and reduces the coplanar probability of those between adjacent O elements, thus effectively inhibiting the generation of O-O dimers under high voltage condition and the loss of surface oxygen. The high-stable interface alleviates the side reaction with electrolyte and the densification of structure, improves the Li⁺ diffusion migration kinetics and reduces the overpotential. Meanwhile, the occupancy and migration path of Li⁺ on the surface layer transforms from two-dimensional order into three-dimensional disorder, which changes the thermodynamic reaction potential. The electrochemical performance particularly voltage attenuation and hysteresis are significantly improved by 2 at% Os doping. The average voltage attenuation per cycle is reduced by more than half from 2.17 mV to 1.01 mV during 300 cycles, and the voltage hysteresis between charge and discharge is reduced from 1.228 V to 0.733 V at the 300th cycle. This provides an idea for studying the mechanism of coordination environment of oxygen and the migration path of Li⁺ for cathode materials.

作为插层锂存储模式下具有最高容量（>280 mAh g ^-1）的锂离子电池正极材料，富锂层状氧化物仍然存在由不稳定的O释放引起的容量衰减、电压衰减和滞后现象。在这项工作中，Os 表面掺杂已应用于 Li _1.2 Ni _0.13 Co _0.13 Mn _0.54 O ₂用于氧骨架的结构尺寸梯度设计，诱导具有三维锂/过渡金属（TM）阳离子无序的表面异质结构。表面氧的八面体配位环境转变为 Li/TM 的随机无序分布，与本体内部的二维有序氧骨架结构不同。这促进了O 2p 未杂化轨道的三维无序排列，降低了相邻O元素之间的共面概率，从而有效地抑制了高压条件下OO二聚体的生成和表面氧的损失。高稳定的界面减轻了与电解质的副反应和结构的致密化，提高了 Li ⁺扩散迁移动力学并降低过电位。同时，Li ⁺在表层的占据和迁移路径从二维有序转变为三维无序，从而改变了热力学反应势。电化学性能，特别是电压衰减和滞后，通过 2 at% 的 Os 掺杂得到显着改善。每循环平均电压衰减在300个循环期间从2.17 mV降低到1.01 mV，并且在第300个循环时充放电之间的电压滞后从1.228 V降低到0.733 V。这为研究氧的配位环境机理和正极材料Li ⁺的迁移路径提供了思路。