The performances of lithium-ion batteries depend on the capability of the electrode materials to exchange lithium ions and electrons faster and reversibly. LiNiO₂ is a promising electrode candidate for achieving high voltage and capacity. However, its industrialization is hindered by surface and bulk instabilities. These instabilities are due to redox processes involving charge transfer between the cations and anions. Therefore, a fundamental understanding based on further experimental evidence is required to resolve the charge transfer between the cation and anion from the surface to the bulk in LiNiO₂. Herein, we resolve the roles of nickel and oxygen in the charge compensation process in Li_xNiO₂ electrodes from the extreme surface down to 30 nm by energy dependent core-level HAXPES supported by an ab initio simulation. We emphasize the central role of oxygen in the bulk charge compensation mechanism from LiNiO₂ to NiO₂ due to the negative charge transfer and bond/charge disproportionation characters of LiNiO₂.

中文翻译：

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深度解析从LiNiO2到NiO2的电荷补偿机制

锂离子电池的性能取决于电极材料更快、可逆地交换锂离子和电子的能力。 LiNiO ₂是实现高电压和高容量的有前途的电极候选者。然而，其工业化受到表面和体积不稳定性的阻碍。这些不稳定性是由于涉及阳离子和阴离子之间的电荷转移的氧化还原过程造成的。因此，需要基于进一步实验证据的基本理解来解决LiNiO ₂中阳离子和阴离子之间从表面到本体的电荷转移。在此，我们通过从头算模拟支持的能量相关核心级 HAXPES 解析了 Li _x NiO ₂电极从极端表面到 30 nm 的电荷补偿过程中镍和氧的作用。由于LiNiO _{2的负电荷转移和键/电荷歧化特性，我们强调了氧在从LiNiO 2}到NiO _{2 的}体电荷补偿机制中的核心作用。