Electrochimica Acta, Vol.300, 26-35, 2019
Dual functions of residue Li-reactive coating with C4H6CoO4 on high-performance LiNiO2 cathode material
Involving more nickel proportion in Ni-rich cathodes, edging to LiNiO2, is an inevitable trend to satisfy the demand of high energy density in lithium-ion batteries, but an inducement for the severer formation of undesirable lithium residues. To overcome the consequent degradation behaviors, a LiCoO2@Co3O4 complex coating layer is successfully realized on the surface of LiNiO2 via a facile wet-chemical method taking advantage of the Li-reactive ability of Co3O4. As a result, the 0.4 wt.% Co modified material exhibits competitively enhanced cyclic performance with 178.1 mAh g(-1) after 50 cycles at 1 C, 11% higher than the pristine one in retention rate. Even at higher rates and temperature, it shows better electrochemical stability as well. The superior electrochemical properties of LiCoO2@Co3O4 coated LiNiO2 is ascribed to the dual-function of the coating method, where Co3O4 is formed during heat treatment and simultaneously reacted with surface lithium residues to generate LiCoO2. In combination of bulk and surface characterization, the significant effects of the coating layer on stabilizing material interface and strengthening the kinetic characteristics for LiNiO2 cathode materials are investigated and elucidated in detail. (C) 2019 Elsevier Ltd. All rights reserved.