Direct recycling of spent Li-Ion cathodes into next-generation Li-rich high Mn content layered oxides

Abstract: The increasing demand for lithium-ion batteries has intensified supply risks associated with nickel and cobalt, motivating recycling strategies that reduce reliance on these critical metals while retaining cathode functionality. This study demonstrates a direct upcycling route that converts spent LiNi0.6Mn0.2Co0.2O2 (NMC622) cathodes into next-generation Li-rich, high Mn content, layered oxides (LMR), following the general formula of Li1+x(Mn, Ni, Co)1–xO2. Spent NMC622 was first recovered from Samsung cells, combined with Li and Mn salts, and subsequently processed via solid-state synthesis. X-ray diffraction confirmed the expected mixed-phase structure, which was indexed to hexagonal (R-3m) and monoclinic (C2/m, Li2MnO3-like) domains. LMR delivered initial discharge capacities of 260 mAh g-1. Partial oxygen substitution with fluorine increased the first-cycle LMR capacity to 289 mAh g-1 and reduced the first-cycle loss. At 20 mA g-1, the upcycled fluorine-containing LMR exhibited improved voltage stabilization and reduced polarization compared to the F-free counterpart. Overall, this work demonstrates a direct cathode upcycling strategy, which switches dependence from costly Ni (in NMC622) to a cheap Mn-based next generation lithium ion cathode material. This lowers critical metal demand and supports resource-efficient circular battery economies that will aid ongoing green energy transitions.