The improvement of the high voltage performance of LiCoO2 by coating LiTaO3via magnetron sputtering

Abstract

Lithium cobalt oxide (LiCoO₂) is one of the most commercially successful cathode materials and has attracted much attention from researchers since its discovery. However, an increase in cut-off voltage generates problems such as structural damage and detrimental side reactions. Under this premise, a layer of LiTaO₃ coating is sputtered on the surface of the LiCoO₂ electrode by magnetron sputtering, which aims to inhibit the structural damage and the occurrence of side reactions under high voltage. Meanwhile, the ionic conductor layer of LiTaO₃ can also promote the transmission process of Li⁺ and improve the power density. The results show that the capacity retention rate of the MS-2 h (magnetron sputtering for 2 hours) electrode is 86.6% at 0.5C for 100 cycles in a voltage range of 3.0–4.6 V, and the capacity of 91 mA h g⁻¹ is achieved at 3C. The cycling stability of the electrode is also effectively improved at high temperature, and the capacity retention rate was 40.9% after 100 cycles at 50 °C. This work proves that the coating of LiTaO₃ on the electrode surface by magnetron sputtering can effectively inhibit the damage of the electrode structure and the occurrence of side reactions during cycling and can promote the transmission of lithium ions.