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 LiAlO 2 layer on the surface of LiCoO 2 /LiNi 0.5 Mn 1.5 O 4 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 LiAlO 2 coating. Electrochemical performance tests show better cycle performance of LiCoO 2 with 1% LiAlO 2 coating. An 85% capacity can be retained over 200 cycles at 1C and 4.5 V cutoff, compared to 61% for uncoated LiCoO 2 . For LiNi 0.5 Mn 1.5 O 4 , 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. Graphical In this study, a novel surface-coating strategy based on a melt curing process is proposed, which forms an ion-conductive LiAlO 2 coating layer on the surface of LiCoO 2 cathode materials. TEM combined with EDS, XPS, etc. confirms the uniform thin layer LiAlO 2 coating, while the electrochemistry measurements prove the high stability of LiCoO 2 with LiAlO 2 coating.