Controlled crystallinity of LiTaO3 surface layer for single-crystalline Ni-rich cathodes for lithium-ion batteries and all-solid-state batteries

Abstract

Various functional materials have been explored as surface-coating layers for Ni-rich cathode materials used in lithium-ion batteries (LIBs) aiming to enhance their long-term cycling performance and electrochemical stability under high-voltage operation. In particular, lithium tantalate (LiTaO3) has received considerable attention as a promising candidate due to its distinct physicochemical properties, including high ionic conductivity, wide voltage window, low band-gap energy, and excellent mechanical strength. These characteristics are beneficial for effective surface stabilization of Ni-rich cathode materials, which currently suffer from poor cycling performance, mainly due to issues related to structural instability with elevated Ni concentrations. In this respect, we report the benefits of surface coating with LiTaO3 on the electrochemical properties of single-crystalline Ni-rich cathode materials (SNCM) for successful implementation in high-energy LIBs. The controlled crystallinity of the LiTaO3 surface layer directly affects the reversibility as well as interfacial stability of the SNCM cathode under various operating conditions. The tailored crystallinity of LiTaO3 surface layer is mainly responsible for enhancing the cycle performance of SNCM cathodes under high-temperature (60 °C) and high-voltage (4.5 V vs. Li/Li+) operations. Our findings will significantly contribute to the development of robust and reliable cathode materials for high-energy LIBs.