One-Pot Spray Pyrolysis Fabrication of Multi-Phase Lithium Manganese Oxide Microsphere Cathodes for Enhanced Lithium-Ion Battery Performance

Abstract

Spinel-type lithium manganese oxide (LMO) cathodes offer low cost, environmental benignity, and strong thermal safety, making them attractive for fast-charge lithium-ion batteries. Their widespread adoption, however, has been hindered by structural degradation associated with the Jahn–Teller distortion of Mn³⁺. Here, we report for the first time a rapid, single-step spray pyrolysis route that produces multi-phase microspheres comprising Sr-doped LiMn₂O₄ spinel, a minor Sr₂Mn₂O₅ phase, and a C2/m layered Li₂MnO₃-like structure, all crystallized directly from a single precursor solution without post-treatment. This continuous aerosol process enables uniform Sr incorporation, precise morphological control, and manufacturing scalability. The synergistic coexistence of these phases provides multiple benefits: Sr doping lowers the Mn³⁺ fraction, suppresses lattice distortion, and stabilizes the spinel framework; the Sr₂Mn₂O₅ phase refines particle morphology and mitigates mechanical stress during cycling; and the layered Li₂MnO₃-like domains enhance structural stability, diversify Li⁺ diffusion pathways, and suppress Mn dissolution and electrolyte side reactions. As a result, the composite cathode delivers improved electrochemical performance, retaining 81.72 mA h g⁻¹ after 400 cycles at 1 C and 76.78 mA h g⁻¹ at 5 C, demonstrating that rapid, single-step spray pyrolysis is an effective and scalable strategy for robust, high-voltage spinel cathodes.