Hydrogenated surface disorder enhances lithium ion battery performance

• Published in: Nano energy 2013-09, Vol.2 (5), p.826-835
• Main Authors: Xia, Ting, Zhang, Wei, Li, Wenjing, Oyler, Nathan A., Liu, Gao, Chen, Xiaobo
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystalline core; Diffusion in nanoscale solids; Diffusion in solids; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Hydrogenation; Lithium ion battery; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Specific materials; Surface disorder; Titanium dioxide nanocrystals; Transport properties of condensed matter (nonelectronic)
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2013.02.005

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. A thin layer of hydrogenated surface disorder on the crystalline TiO2 electrode induces larger capacity, higher Coulombic efficiency, enhances the charge/discharge rate performance, and extends longer stability, compared to the crystalline TiO2 electrode, possibly due to facilitated lithium ion transport and alleviated structural distortion during the lithium insertion/extraction process across the crystalline TiO2 electrode, and the fast ion exchange rates in the hydrogenated disordered layer. [Display omitted] ► A thin hydrogenated surface disorder layer on crystalline TiO2 electrode induces larger capacity. ► It induces higher Coulombic efficiency, better rate performance, and longer stability. ► It facilitates transport and alleviates structural distortion in the electrode. ► The fast ion exchange rate may play a role in the hydrogenated disordered layer.