Modification of TiO₂ powder via atmospheric dielectric barrier discharge treatment for high performance lithium-ion battery anodes

The main objective of this study is to improve the electrochemical performances of TiO₂ Li-ion anode material by introducing plasma treatment on TiO₂ powder. A specially designed atmospheric dielectric barrier discharge plasma generator feasible to modify powders is proposed. The rate capacity of 20 min plasma-treated TiO₂ anode revealed nearly 20% increment as compared to that of pristine TiO₂ at the rates of 0.5, 1, 2, 5, 10 C. As-treated TiO₂ was first analyzed by the X-ray diffractometer and high resolution transmission electron microscope confirmed that there was no noticeable surface morphology and microstructure change from plasma treatment. In addition, plasma-treated TiO₂ was reduced with increasing treatment duration. Significant amount of excited argon (Ar^∗) and excitation of a nitrogen second positive system (N₂ ^∗) were discovered using optical emission spectroscopy (OES). It was believed that Ar^∗ and N₂ ^∗ contributed to TiO₂ surface reduction as companied by formation of oxygen vacancy. A higher amount of oxygen vacancy increases the chance of allowing excited nitrogen to dope onto surface of TiO₂ particle. Electrochemical properties of TiO₂ were raised due to the production of oxygen vacancy and nitrogen doping. These findings enhance the understanding of the atmospheric plasma treatment on the potential application of TiO₂ anode material in Li-ion battery.