In-situ grown Li-Ti-O layer derived by atomic layer deposition to improve the Li storage performance of Li2TiSiO5 anode materials

Abstract

Li2TiSiO5 (LTSO) fibers coated by an in-situ grown Li-Ti-O layer are synthesized through ALD and post thermal treatment. Due to the ALD coating technique, precise thickness control and conformal coating layer can be realized. Through post-heating treatment, the ALD-coated TiOx layer can react with lithium residues in the host materials, forming the Li-Ti-O coating layer. Benefiting from the Li-ion conductive feature of the Li-Ti-O phase, Li-Ti-O coated LTSO fibers exhibit a high reversible capacity of 229 mA h g−1 at a current density of 0.5 A g−1 after 400 cycles in the potential range of 0.1–3 V (vs. Li+/Li). Even at a high current density of 5 A g−1, a reversible capacity of 154 mA h g−1 can be achieved. Electrochemical impedance spectra (EIS) demonstrate that the Li-Ti-O coated LTSO fibers have an apparent chemical Li-ion diffusion coefficient of 1.43 × 10−15 cm2 s−1 and decreased charge transfer resistance compared to that of pristine LTSO fibers, leading to faster Li-ion transfer kinetics and improved electrochemical performances.