High energy density and micrometer-sized d0-free disordered rocksalt cathodes

Abstract

The rapidly increasing demand for Li-ion batteries motivates the search for low-cost cathode materials free of critical metals, and with a high energy density and stable cycling performance. Disordered rocksalt oxide (DRX) cathodes derived from abundant metals are particularly promising as they can achieve higher energy densities than commercial, Ni- and/or Co-containing cathodes. However, their further development is hindered by the requirement for a redox-inactive “d⁰” transition metal to stabilize the disordered structure, and particle nanosizing to achieve appreciable capacity, limiting their energy density and cycle life. We report a new class of d⁰-free DRX cathodes realized through synthetic control of atomic disorder. Impressively, the removal of d⁰ species enables a micrometer-sized manganese-based DRX cathode to achieve a high capacity (220 mAh g⁻¹) while extending its cycle life by more than 3×. The discovery of d⁰-free DRX opens a large, unexplored compositional space and represents a significant step toward the commercialization of inexpensive and Earth-abundant Li-ion cathodes.