NiO-Coated LiMn ₂ O ₄ Cathodes: Enhanced Electrochemical Performance through Surface Modification

LiMn 2 O 4 has emerged as a promising cathode material for lithium-ion batteries, attributed to its low cost, environmental benignity, and intrinsic safety merits. However, its practical implementation is hindered by severe capacity degradation during long-term cycling. To address this challenge, a LiMn 2 O 4 surface modification strategy via NiO coating was adopted in this study to enhance the structural and electrochemical stability of LiMn 2 O 4 . A series of LiMn 2 O 4 samples coated with NiO at different loadings (0.5–2.5 wt%) were synthesized by a chemical precipitation method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the successful formation of a uniform NiO coating layer on the surface of LiMn 2 O 4 , without altering the bulk spinel structure of LiMn 2 O 4 . Electrochemical evaluations revealed that the LiMn 2 O 4 sample coated with 1.5 wt% NiO exhibited the optimal performance, it delivered an initial discharge capacity of 116.8 mAh·g -1 at 0.2C and retained 91.8% of its capacity after 100 cycles at 2C, which significantly outperformed the pristine LiMn 2 O 4 sample (74.9% retention) The improved electrochemical performance can be attributed to the fact that the NiO coating layer effectively suppresses the side reactions between the electrolyte and the electrode, thereby enhancing the stability of LiMn 2 O 4 during high-rate charge-discharge processes.