EN06.04.29 : A First-Principles Investigation of Lithium Intercalation and Diffusion in Titanium Dioxide with Oxygen Vacancy

5:00 PM–7:00 PM Apr 3, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Hsiu-Liang Yeh1 Shih-Hsuan Tai1 Chieh-Ming Hsieh1 Bor Kae Chang1

1, National Central University, Taoyuan City, , Taiwan

Titanium dioxide has recently attracted focus as a potential anode material in lithium-ion rechargeable batteries (LiBs) because of the low cost, abundant source, light weight, safety, and high theoretical capacity. However, the practical application of TiO2 is restricted by its poor electronic conductivity and inefficient lithium diffusion. Previous experimental studies have demonstrated that the incorporation of oxygen vacancy into TiO2 nanostructures as a strategy to enhance anode material performances. In this work, three most common polymorphs of TiO2 were investigated for potential as lithium-ion battery anode materials: anatase, rutile and TiO2(B). Each phase was modeled and first-principles study based on density functional theory (DFT) calculations were employed to investigate the intercalation and diffusion behavior of lithium at dilute concentrations in TiO2 with/without an oxygen vacancy. Total energies of possible intercalation sites were first calculated to determine favorable sites among the three phases. Furthermore, all lithium diffusion pathways form one stable site to another were examined by climbing image nudged elastic band method. To understand the effect of oxygen vacancy on the lithium diffusion mechanism, energy barriers of lithium diffusion for pristine and oxygen-defective TiO2 structures were calculated and compared. In addition, the electronic structures of TiO2 with oxygen vacancy were compared to pristine TiO2. The results indicate that among the three polymorphs, TiO2(B) may the better choice for use as anode material after oxygen vacancy creation because of lower diffusion energy barrier change and larger band gap reduction.