Ultrathin ZrO2 on LiNi0.5Mn0.3Co0.2O2 electrode surface via atomic layer deposition for high-voltage operation in lithium-ion batteries

High-voltage operation in LiNi0.5Mn0.3Co0.2O2 (NMC532) is an attractive strategy to meet the demands for practical application of high energy density lithium-ion batteries (LIBs). However, a serious problem at high cut-off voltage is the capacity fading during charge-discharge cycling, caused by electrolyte decomposition and dissolution of cathode materials. Herein, we fabricated an ultrathin ZrO2 coating on the surface of the as-prepared NMC532 electrode via atomic layer deposition (ALD) to improve the electrochemical performances of the high-voltage NMC532/graphite system. The capacity retention and rate capability of NMC 532 electrode at high voltage (4.6 V) operation were improved by the ZrO2 coating. Cyclic voltammetry, X-ray photoelectron spectroscopy, and X-ray diffraction analyses of ZrO2-coated NMC532 electrode revealed that the enhanced electrochemical performance was due to the reduced side reaction, structural disordering, and polarization at the cathode surface. Thus, ZrO2 coating of the as-prepared electrode by ALD is a promising technique to maintain the high electrochemical performance of LIBs during high-voltage operations.