In
the past several years, cation-disordered Li-excess rocksalts
(DRXs) have quickly emerged as a new class of promising high-energy
Li-ion battery (LIB) cathode materials. These oxides and oxyfluorides
often consist of Earth-abundant elements, along with Co-free chemistry,
a wide compositional space, and large charge storage capacities. In
this Review, we provide an overview on the recent advances in DRX
cathodes, with an emphasis on compositions and synthesis, charge storage
mechanisms, performances in battery cells, key factors influencing
electrochemical performance, and materials degradation mechanisms.
As DRX cathode materials are fairly new and they have not yet gone
through the extensive optimization process needed for commercialization,
we provide perspectives on future directions in developing DRXs that
are better alternatives to today’s LIB cathodes.