Disordered Rock-Salt Oxide Cathode for Next-Generation Energy Storage

Disordered rock-salt (DRX) oxides break the conventional requirement of long-range cation ordering for lithium-ion battery cathodes. Their lithium-excess, cation-disordered framework enables three-dimensional Li+ percolation, broad compositional flexibility, and synergistic cation–anion redox chemistry, offering a viable route toward high-capacity, Co/Ni-free cathodes. Despite reversible capacities exceeding 250–300 mAh·g−1, practical implementation is hindered by poor electronic conductivity, voltage hysteresis, oxygen loss, transition-metal migration, and synthesis challenges. This perspective summarizes progress from two aspects: synthesis methodology and performance optimization. Conventional solid-state, mechanochemical, and sol-gel routes are discussed, followed by emerging strategies including molten-salt, microwave, Joule heating, and thermal shock synthesis. We then highlight performance enhancement strategies such as compositional design, anion engineering, short-range order regulation, particle-size and single-crystal control, surface coating, and conductive network construction. Finally, we discuss remaining challenges and future directions for developing scalable, low-cost, high-energy DRX cathodes, particularly toward Co/Ni-free and ultimately d0-free chemistries.