Active–Inactive Molten Salt Synthesis of Li- and Mn-Rich Layered Oxide Single Crystals as Cathode Materials for All-Solid-State Batteries

Micrometer-sized layered oxide single crystals are considered promising cathode materials for all-solid-state batteries (ASSBs) due to their superior properties compared to those of polycrystalline forms. In addition, Li- and Mn-rich layered oxides (LMRO), represented by the formula x Li 2 MnO 3 ·(1– x )LiTMO 2 (where TM = Ni, Co, and Mn), are noted for their higher energy densities and cost-effectiveness relative to conventional layered LiNi 1– y – z Co y Mn z O 2 materials. In this regard, micrometer-sized, monodisperse, and discrete LMRO single crystals are synthesized using an active–inactive molten salt method that exploits the high reactivity of LiOH and the negligible reactivity of Li 2 SO 4 . This approach overcomes the challenges associated with conventional molten salt synthesis in controlling the structure and composition of LMRO. The chemical reactivities of lithium salts (Li…