To improve the cycle performance, zLi2TiO3@LiNi0.5Mn0.5O2 (z=0, 1, 3, and 5 mol%) cathode materials have been successfully prepared via a syn-lithiation strategy. The high-resolution transmission electron microscope (HRTEM) structural analysis results shows that Li2TiO3 is evenly coated on the surface of LiNi0.5Mn0.5O2, with the thickness of the coating layer of approximately 10 nm. The electrochemical characterizations of the synthesized zLi2TiO3@LiNi0.5Mn0.5O2 suggests that 1 mol% Li2TiO3@LiNi0.5Mn0.5O2 electrode shows the best electrochemical performance, including the highest capacity and best cycle stability and rate performance. The capacity retention at 25 °C is improved by approximately 23% by the 1 mol% Li2TiO3 coating. The improved cycling performance of LiNi0.5Mn0.5O2 arises from the presence of the Li2TiO3 surface layer, which suppresses the direct contact between the active materials and the electrolytes, enhances the lithium ion diffusion through the electrode/electrolyte interface, improves the BET area, stabilizes the structure and prevents the pulverization of the active materials during repeated charging/discharging. The XPS results showed that Li2TiO3 coating layer could inhibit electrolyte decomposition, and the decomposition of electrolyte on the surface of coating electrode is different from that of LiNi0.5Mn0.5O2 electrode.

Effects of Li2TiO3-coating on the structure and the electrochemical properties of LiNi0.5Mn0.5O2 cathode materials at high voltages

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.