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

LiMn[Formula: see text]O[Formula: see text] 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[Formula: see text]O[Formula: see text] 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[Formula: see text]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[Formula: see text]O[Formula: see text], without altering the bulk spinel structure of LiMn[Formula: see text]O[Formula: see text]. Electrochemical evaluations revealed that the LiMn[Formula: see text]O[Formula: see text] sample coated with 1.5[Formula: see text]wt.% NiO exhibited the optimal performance, it delivered an initial discharge capacity of 116.8[Formula: see text][Formula: see text] at 0.2C and retained 91.8% of its capacity after 100 cycles at 2C, which significantly outperformed the pristine LiMn[Formula: see text]O[Formula: see text] 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.