Yano, A., Shikano, M., Ueda, A., Sakaebe, H.
Improved electrochemical performances of LiCoO 2 at elevated voltage and temperature with an in situ formed spinel coating layer. Surface engineering strategies of layered LiCoO 2 cathode material to realize high-energy and high-voltage Li-ion cells. Narrowing the gap between theoretical and practical capacities in Li-ion layered oxide cathode materials. Synthetic control of kinetic reaction pathway and cationic ordering in high-Ni layered oxide cathodes. Understanding electrochemical potentials of cathode materials in rechargeable batteries. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries. Metal segregation in hierarchically structured cathode materials for high-energy lithium batteries. Li-ion battery materials: present and future. Evolution of strategies for modern rechargeable batteries. Ultimate limits to intercalation reactions for lithium batteries. These dopants contribute through different mechanisms and synergistically promote the cycle stability of LiCoO 2 at 4.6 V. We also show that, even in trace amounts, Ti segregates significantly at grain boundaries and on the surface, modifying the microstructure of the particles while stabilizing the surface oxygen at high voltages. Using state-of-the-art synchrotron X-ray imaging and spectroscopic techniques, we report the incorporation of Mg and Al into the LiCoO 2 lattice, which inhibits the undesired phase transition at voltages above 4.5 V. Here, we achieve stable cycling of LiCoO 2 at 4.6 V (versus Li/Li +) through trace Ti–Mg–Al co-doping. However, practical adoption of high-voltage charging is hindered by LiCoO 2’s structural instability at the deeply delithiated state and the associated safety concerns. LiCoO 2 is a dominant cathode material for lithium-ion (Li-ion) batteries due to its high volumetric energy density, which could potentially be further improved by charging to high voltages.