Lithium cobalt oxide (LCO) is the dominating cathode materials for lithium-ion batteries (LIBs) deployed in consumer electronic devices for its superior volumetric energy density and electrochemical performances. The constantly increasing demands of higher energy density urge to develop high-voltage LCO via a variety of strategies. However, the corresponding modification mechanism, especially the influence of the long- and short-range structural transitions at high-voltage on electrochemical performance, is still not well understood and needs further exploration. Based on ss-NMR, in-situ X-ray diffraction, and electrochemical performance results, it is revealed that the H3 to H1-3 phase transition dictates the structural reversibility and stability of LCO, thereby determining the electrochemical performance. The introduction of La and Al ions could postpone the appearance of H1-3 phase and induce various types of local environments to alleviate the volume variation at the atomic level, leading to better reversibility of the H1-3 phase and smaller lattice strain, and significantly improved cycle performance. Such a comprehensive long-range, local, and electronic structure characterization enables an in-depth understanding of the structural evolution of LCO, providing a guiding principle for developing high-voltage LCO for high energy density LIBs.

钴酸锂（LCO）是用于消费电子设备的锂离子电池（LIB）的主要阴极材料，具有出色的体积能密度和电化学性能。对更高能量密度的不断增长的需求促使人们通过各种策略来开发高压LCO 。然而，相应的修饰机理，特别是高压下长程和短程结构转变对电化学性能的影响，仍未被很好地理解，需要进一步探索。基于ss-NMR，原位X射线衍射和电化学性能结果表明，H3至H1-3的相变决定了LCO的结构可逆性和稳定性，从而决定了电化学性能。La和Al离子的引入可以推迟H1-3相的出现并诱导各种局部环境以减轻原子水平的体积变化，从而导致H1-3相具有更好的可逆性和较小的晶格应变，并且改善了循环性能。这种全面的远程，局部和电子结构表征可以深入了解LCO的结构演变，为开发用于高能量密度LIB的高压LCO提供指导原则。