Enhancement on the Cycling Stability of the Layered Ni-Rich Oxide Cathode by In-Situ Fabricating Nano-Thickness Cation-Mixing Layers

Abstract

The layered Ni-rich oxide cathode (LiNi0.8Co0.1Mn0.1O2) has been significantly attractive due to its large reversible capacity (200 mAh g−1). However, the layered Ni-rich oxide cathode suffers from a tremendous structural degradation during long-term cycling, causing the drastic rise of electrode impedance and deterioration of the capacity retention. In this paper, we develop a novel and facile approach to stabilize its structure by per-cycling of the layered Ni-rich oxide cathode at high voltage of 4.5 V (vs Li/Li+). The nano-thickness cation-mixing layers with Fm-3m structure were in-situ formed on the layered Ni-rich oxide LiNi0.8Co0.1Mn0.1O2 cathode by the surface structural transition from rhombohedral phase to cubic phase. The as-prepared LiNi0.8Co0.1Mn0.1O2 cathode coated with the nano-thickness cation-mixing layers shows superior cycling life at a cutoff voltage of 4.3 V, and it keeps a capacity retention of 83% after 500 cycles, which could be attributed to that the nano-thickness cation-mixing layers stabilize the structure of LiNi0.8Co0.1Mn0.1O2 during long-term cycling.