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

Abstract

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 20min plasma-treated TiO2 anode revealed nearly 20% increment as compared to that of pristine TiO2 at the rates of 0.5, 1, 2, 5, 10C. 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.