National and Local Joint Engineering Laboratory for Lithium-Ion Batteries and Materials Preparation Technology,Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,Kunming 650093, China
Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cobalt-free cathode material for lithium-ion batteries (LIBs) due to its high operating voltage (>4.7 V) and excellent bulk energy density (≥650 Wh·kg-1). However, the commercial application of this material is hindered by its poor cyclability at high operating voltage. This work successfully constructed an inorganic conductive coating layer, Li1.4Y0.4Ti1.6(PO4)3 (LYTP), on the surface of LNMO using the gel-sol method. The study comprehensively investigated the surface morphology,crystal structure and electrochemical properties of LNMO before and after modification. The results indicate that the LYTP surface modification has a good multifunctional protective layer effect. It effectively reduces the dissolution of manganese in the electrolyte and improves the migration efficiency of lithium ions. The capacity retention of LNMO@LYTP remains high at 82% even after 500 cycles, which is significantly higher than that of the uncapped lithium nickel manganate cathode. The LNMO@LYTP has a discharge specific capacity of 116 mAh·g-1 even at 10C multiplication. This study contributes to the field of surface modification and provides ideas for further improving the electrochemical performance of other high-voltage manganese-based LIBs.