Atomic layer deposition of Al2O3 on LiNi0.68Co0.10Mn0.22O2 for enhanced electrochemical performance

Abstract

Although there have been many studies on atomic layer deposition of Al2O3 to improve the electrochemical performances of ternary cathode materials, few studies considered the harsh conditions such as high temperature and high voltage at the same time. In this work, the Al2O3 passivation layer is employed to coat the high nickel (Ni) LiNi0.68Co0.10Mn0.22O2 cathode through atomic layer deposition (ALD) approach. The Al2O3 coated LiNi0.68Co0.10Mn0.22O2 presents superior cycling stability and rate capability than the pristine at the cut-off voltage of 2.7–4.4 V under room temperature. Furthermore, under the harsh condition at high temperature of 60 °C or at high voltage of 2.7–4.8 V, the Al2O3 coated LiNi0.68Co0.10Mn0.22O2 also shows significantly improved performances than the pristine. The superior electrochemical performance of Al2O3 coated LiNi0.68Co0.10Mn0.22O2 could be attributed to the enhanced interfacial stability, the mitigated side reactions with electrolyte and the better maintained lithium ion diffusion kinetics. Manipulating the surface coating chemistry and evaluating the performance under harsh condition provide a useful approach for fast screening of effective surface modification technology, which might significantly advance the development of high energy density cathode materials.