Effects of MoO3 coating on the structure and electrochemical performance of high-voltage spinel LiNi0.5Mn1.5O4

High-voltage spinel LiNi0.5Mn1.5O4 cathode material suffers from degradation of electrochemical cycling performance, particularly at elevated temperatures, hindering its successful commercialization. Here, we report that coating this cathode material with MoO3 oxides shows significantly improved electrochemical cycling performance at both room and elevated temperatures. The coated LiNi0.5Mn1.5O4 half-cell has a capacity retention of only 76%, while it is 90%, 92%, and 93% for 1 wt%, 2 wt%, and 3 wt% MoO3-coated LiNi0.5Mn1.5O4, respectively, after 100 cycles at 55 degrees C. The improved electrochemical cycling performance is attributed to the stabilized structure of LiNi0.5Mn1.5O4 by migration of Mo6+ into the former, particularly in the surface region during the MoO3 coating process, accompanied by a reduction in surface Ni content and an initial NiO impurity. Furthermore, the electrolyte decomposition and Ni and Mn metal dissolution are reduced by surface MoO3 coating.