Potential Alternatives for Advanced Energy Material Processing in High Performance Li-ion Batteries (LIBs) via Atmospheric Pressure Plasma Treatment

A new processing technique by atmospheric pressure plasma (APP) jet treatment of LIBs was introduced. Ar/N$_{\mathrm{2}}$ plasma enhanced the high-rate anode performance of Li$_{\mathrm{4}}$Ti$_{\mathrm{5}}$O$_{\mathrm{12}}$. Oxygen vacancies were discovered and nitrogen doping were achieved by the surface reaction between pristine Li$_{\mathrm{4}}$Ti$_{\mathrm{5}}$O$_{\mathrm{12}}$ and plasma reactive species (N$^{\mathrm{\ast }}$ and N$_{\mathrm{2}}^{\mathrm{+}})$. Electrochemical impedance spectra confirm that plasma modification increases Li ions diffusivity and reduces internal charge-transfer resistance, leading to a superior capacity (132 mAh/g) and excellent stability with negligible capacity decay over 100 cycles under 10C rate. Besides 2D material surface treatment, a specially designed APP generator that are feasible to modify 3D TiO$_{\mathrm{2}}$ powders is proposed. The rate capacity of 20 min plasma treated TiO$_{\mathrm{2}}$ exhibited 20{\%} increment. Plasma diagnosis revealed that excited Ar and N$_{\mathrm{2}}$ was contributed to TiO$_{\mathrm{2}}$ surface reduction as companied by formation of oxygen vacancy. A higher amount of oxygen vacancy increased the chance for excited nitrogen doped onto surface of TiO$_{\mathrm{2}}$ particle. These findings promote the understanding of APP on processing anode materials in high performance LIBs.