Enhanced electrochemical performance of the layered nickel-rich oxide cathode by KMnO4 treatment precursor

LiNi0.8Mn0.1Co0.1O2 cathode material with excellent electrochemical properties was successfully prepared by treating precursor with strong oxidant KMnO4. It exhibited an excellent cycle performance without capacity decay after 50 cycles. The results indicated that a nanoscale thickness MnO2 layer formed on LiNi0.8Mn0.1Co0.1O2, and some Mn4+ ions were introduced into the outer surface of the bulk phase. Simultaneously, some portion of Ni2+ ions migrate from the transition metal layer to lithium layer which could prevent interslab collapse and improve structural stability. Electrochemical impedance spectroscopy analysis confirmed that the electrochemical impedance increase of the electrode after 50 cycles was significantly suppressed. Combined with X-ray photoelectron spectroscopy tests of the cycled electrodes, it was proved that electrolyte decomposition on the surface of the modified LiNi0.8Mn0.1Co0.1O2 was greatly suppressed, and a thin SEI film formed. (C) 2019 Elsevier B.V. All rights reserved.