Hydrogenated surface disorder enhances lithium ion battery performance

TiO₂, well known for its photocatalytic properties, has also been studied as a safer anode material for lithium ion batteries compared to graphite. However, improvements are needed to address the limited lithium ion diffusion within the host and the structural distortion during lithium insertion/extraction. Here, we demonstrate that a thin layer of hydrogenated surface disorder on the crystalline TiO₂ electrode induces better electrochemical energy storage performance, better charge/discharge rate performance, larger capacity and longer stability. The reasons for these improvements are explored in terms of the facilitation of lithium ion transport within the disordered layer and the alleviation of structural distortion during the lithium insertion/extraction process, and the faster ion exchange rates in the hydrogenated disordered layer.