Enhancing the Electrochemical Performance of High Voltage LiNi_0.5Mn_1.5O₄ Cathode Materials by Surface Modification with Li_1.3Al_0.3Ti_1.7(PO₄)₃/C

Abstract

A novel method for surface modification of LiNi0.5Mn1.5O4 (LNMO) was proposed, in which a hybrid layer combined by Li1.3Al0.3Ti1.7(PO4)3 (LATP) and carbon (C) composite on LNMO material were connected by lithium iodide. Structure and morphology analyses illustrated that a higher contact area of active substances was achieved by the LATP/C composite layer without changing the original crystal structure of LNMO. XPS analysis proved that I− promoted the reduction of trace Mn4+, resulting in a higher ion conductivity. Galvanostatic charge–discharge tests exhibited the capacity of the LNMO with 5% LATP/C improved with 35.83% at 25 °C and 95.77% at 50 °C, respectively, compared with the bare after 100 cycles, implying the modification of high-temperature deterioration. EIS results demonstrated that one order of magnitude of improvement of the lithium-ion diffusion coefficient of LATP/C-LNMO was achieved (3.04 × 10−11 S cm−1). In conclusion, the effective low-temperature modification strategy improved the ionic and electronic conductivities of the cathode and suppressed the side reactions of high-temperature treatment.

Keywords

• solvent recrystallization
• lithium iodide
• LATP/C composite
• LiNi_0.5Mn_1.5O₄ cathode
• low temperature