Enhanced Electrochemical Performance of 4.5 V LiCoO₂ with LiAlO₂ Coating via a Novel Melt Curing Coating Method

Surface coating is an efficient way to reduce side reactions between cathode materials and electrolytes, thus enhancing the cycle stability of cathode materials. In this study, a novel surface-coating strategy based on the melt curing process is introduced, which forms an ionic conductive LiAlO₂ layer on the surface of LiCoO₂/LiNi_0.5Mn_1.5O₄ cathode materials and enhances the cycle stability of these cathode materials. Comprehensive characterizations, including scanning electron microscopy, energy dispersive spectrometer, and transmission electron microscopy (TEM) confirm the uniformity and thin LiAlO₂ coating. Electrochemical performance tests show better cycle performance of LiCoO₂ with 1% LiAlO₂ coating. An 85% capacity can be retained over 200 cycles at 1C and 4.5 V cutoff, compared to 61% for uncoated LiCoO₂. For LiNi_0.5Mn_1.5O₄, the coated sample shows 94.5% capacity retention after 300 cycles at 1C, while the capacity of the uncoated sample decays to 64.6% under the same condition. These findings underscore the effectiveness and universality of this surface-coating strategy.