A comparative study of increased lithium storage with low resistance at structural defects in amorphous titanium dioxide electrode

Various studies are conducted with an aim to increase the capacity and reduce of the lithium diffusion resistance during the charge/discharge of titanium oxide (TiO₂), which is used as anode material in lithium-ion batteries. However, it is difficult to overcome the limited storage capacity and high diffusion resistance because of the intrinsic crystalline features of TiO₂. This study demonstrates that the lithium storage limit and high lithium diffusion resistance of crystalline titanium oxide (c-TiO₂) can be overcome by using amorphous titanium oxide (a-TiO₂). The results of X-ray diffraction, X-ray absorption spectroscopy, and galvanostatic intermittent titration show that a-TiO₂ can store more Li-ions and has a reduced lithium diffusion resistance than c-TiO₂. In contrast, the lithium storage of the crystalline structure is limited and its lithium diffusion resistance is high. The better performance of a-TiO₂ can be ascribed to anomalous amorphous lithium storage sites, which provide additional lithium storage and open lithium diffusion paths.