Enhancing the Electrochemical Performance of Li₂-xMnO₃ via Dual Strategies: Using MOF-Derived Manganese Oxide Precursor and Tuning Li Content

Abstract

Cathode materials play a crucial role in determining the electrochemical properties and fabrication cost of Lithium-ion batteries (LIBs). Li2MnO3 has garnered increasing attentions due to its high theoretical capacity, but it suffers from severe issues, such as structural deterioration and irreversible capacity loss. In this paper, we propose a novel strategy to synthesize Li2-xMnO3 cathodes using MOF-derived manganese oxide via a simple solid-state reaction. When used as cathodes for LIBs, the MOF-Li2MnO3 exhibits a high reversible capacity of 92.5 mAh g-1 after 120 cycles at 25 mA g-1, as compared to pristine Li2MnO3 (31.7 mAh g-1). Additionally, hybrid phases including orthorhombic-LiMnO2 and cubic LiMn2O4 are introduced into Li-deficient materials, which exhibit different electrochemical behaviors from MOF-Li2MnO3. The MOF-Li1.75MnO3 delivers an unprecedented capacity of 151.9 mAh g-1 after 120 cycles at 25 mA g-1. Overall, the synergistic effect of adopting MOF-derived precursor and inducing multiphase by tuning Li content is conducive to enhancing the electrochemical performance of Li2MnO3 cathode.