Suppressing the voltage decay of Li1.2Mn0.6Ni0.2O2 cathode materials enabled by LiMn0.8Fe0.2PO4/C for long-cycling lithium-ion batteries

Abstract

Li-rich layered oxides can provide high energy density, but their further application is hindered by capacity decrease and voltage decay in the course of cycling. Herein, we blended layered oxide Li1.2Mn0.6Ni0.2O2 (LL) with olivine structured LiMn0.8Fe0.2PO4/C (LFMP) cathode material via a simple method, with improved results of excellent cycle stability, low voltage decay and good thermal stability. The result of TEM and ICP reveals that the LL enabled by LFMP can mitigate the surface-induced phase transition (layered to spinel) and suppress Mn dissolution of LL. As a consequence of CV and GITT test and analysis, the buffer effect of LFMP for LL is benefit to support the layered structure in subsequent cycles, which can provide the long cycle capacity and lower voltage decay for the hybrid materials.