Enhanced cycling stability of 4.6 V LiCoO${}_2$ cathodes by inhibiting catalytic activity of its interface via MXene modification

LiCoO${}_2$ plays a key role in energy storage devices due to its high energy density. And the volumetric energy density of LiCoO${}_2$ cathode can be significantly improved by increasing the charging cut-off voltage to 4.6 V. However, the increase in resistance at the LiCoO${}_2$ interface, and the damage to the LiCoO${}_2$ from the outside to the inside by the HF generated that caused by the decomposition of the organic electrolyte and LiPF${}_6$ under 4.6 V conditions are not conducive to structural stability during cycling. Here, it is shown that the decomposition of electrolyte and LiPF${}_6$ is effectively mitigated by inhibiting the interfacial catalytic activity of LiCoO${}_2$ using an atomically thin layer of MXenes as a interlayer. Density functional theory results suggest that the decomposition energy of LiPF${}_6$ is 1.13 and 3.21 eV at the interface of LiCoO${}_2$ and MXenes, respectively. Time of Flight Secondary Ion Mass Spectrometry results further indicate that the decomposition products of the organic electrolyte and LiPF${}_6$ have a thinner thickness at the interface of MXenes (5 nm) than LiCoO${}_2$ (10 nm). This study provides a new and universal strategy for stabilizing the cathode interface to support the development of high energy density lithium-ion batteries. (© 2023 Wiley‐VCH GmbH)