Enhancing the Electrochemical Performance of High Voltage LiNi 0.5 Mn 1.5 O 4 Cathode Materials by Surface Modification with Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 /C.

A novel method for surface modification of LiNi 0.5 Mn 1.5 O 4 (LNMO) was proposed, in which a hybrid layer combined by Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 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 Mn 4+ , 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.