Achieving high initial coulombic efficiency and low voltage dropping in Li-rich Mn-based cathode materials by Metal-Organic frameworks-derived coating

Li-rich Mn-based oxides (LRMOs) are promising cathode materials for next-generation Li-ion batteries because of their high voltage, high capacity, and low cost. However, the low initial Coulombic efficiency (ICE), severe capacity fading and voltage dropping during cycling hinder their large-scale application of LRMOs. Hence, we propose a facile Metal-Organic Frameworks (MOF)-self-assembly coating strategy to modify LRMOs with CoxOy/C coating (LRMO@CoxOy/C). The CoxOy/C layer can alleviate the side-reaction between the electrolyte and cathode materials, and enhance both ion-diffusion and electrons-transportation speed throughout the surface of the electrode materials. In addition, the CoxOy/C layer suppresses the lattice oxygen release and improve structural stability of LRMOs during long-term cycling. Consequently, the LRMO@CoxOy/C cathode shows a high ICE of 91.5% and slow voltage dropping of only 2 mV/cycle at 0.2 C. After 300 cycles, it still delivers a high discharge capacity of 210.7 mAh.g(-1) at 0.5 C with a capacity retention of similar to 80%. This work provides a novel approach to achieve next-generation high-energy density cathode materials.