Boosting the cycling performance of spinel LiMn2O4 by in situ MnBO3 coating

Abstract

Spinel LiMn2O4 (LMO) is a promising cathode material for lithium-ion batteries (LIBs) due to its low cost, high safety, and high energy density. However, surface dissolution of manganese and irreversible phase transitions reduce its long-term cycling performance. Although surface coating is a promising strategy for improving the structural stability of LMO, the commonly used coating process is tedious and complicated. In this work, a one-step sintering process is developed to prepare LMO materials coated in situ with MnBO3. It is found that the MnBO3 layer formed in this way is uniformly coated on the surface of LMO, and effectively suppresses Mn dissolution and undesirable phase transition during repeated charge/discharge cycles. Furthermore, the MnBO3-coated LMO has improved electrode kinetics, demonstrating significantly improved rate performance compared to the pristine LMO. As a result, the optimized LMO sample exhibits 85.2% capacity retention after 1000 cycles at 1 C and still can deliver 96 mAh g−1, even at 5 C. This work proposes a facile and efficient coating strategy for improving the electrochemical performance of LMO as a cathode material for LIBs.