High-Voltage Oxide Cathode Materials

I will discuss about electrochemomechanical instabilities, self healing, and degradation mitigation strategies in oxide cathodes [Chemical Reviews 123 (2022) 811], such as lanthurization surface treatment [Nature Energy 8 (2023) 159]. Co- and Ni-free disordered rocksalt cathodes utilize oxygen redox to increase the energy density of lithium-ion batteries, but it is challenging to achieve good cycle life at high voltages >4.5V. We report a family of Li-excess Mn-rich cathodes that integrates rocksalt- and polyanion-type (DRXPS) structures. Following design rules for cation filling and ordering, we demonstrate the bulk incorporation of polyanion groups into the rocksalt lattice. This integration bridges the two primary families of lithium-ion battery cathodes - layered/spinel and phosphate oxides - dramatically enhancing the cycling stability of disordered rocksalt cathodes with 4.8V upper cut-off voltage. The DRXPS cathode exhibits high gravimetric energy densities above 1,100Wh/kg and >70% retention over 100 cycles [Nature Energy (2024) 10.1038/s41560-024-01615-6].