TiNbO4‐coated industrial submicron Si anode for high‐performance Li‐ion batteries

Abstract

AbstractSilicon (Si) is a promising anode material for Li‐ion batteries but suffers from volume change during (de)lithiation, leading to electrode pulverization and capacity decay. To address this issue, we introduced a zero‐strain Li‐ion conductor TiNbO4 (TNO) coating on the surface of industrial submicron Si using a simple precipitation method. The density functional theory calculation confirmed TNO as an excellent coating layer to alleviate silicon expansion and benefit to the Li diffusion. The resulting compounds were characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscope, X‐ray photoelectron spectroscopy, half‐cell charge–discharge tests, and cyclic voltammetry and showed that amorphous TNO was well distributed on the Si particles and can effectively improve the Si anode's cycle performance. After 120 cycles, the TNO‐coated Si anode retained 565 mA h g−1 capacity under 0.1 C, which is better than that of pure Si with less than 100 mA h g−1.