One-step argon/nitrogen binary plasma jet irradiation of Li4Ti5O12 for stable high-rate lithium ion battery anodes

• Published in: Journal of power sources 2015-02, Vol.275, p.660-667
• Main Authors: Lan, Chun-Kai, Chuang, Shang-I., Bao, Qi, Liao, Yen-Ting, Duh, Jenq-Gong
• Format: Article
• Language: English
• Subjects: Atmospheric pressure plasma; Lithium titanate; Oxygen vacancy
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2014.11.074

Atmospheric pressure Ar/N2 binary plasma jet irradiation has been introduced into the manufacturing process of lithium ions batteries as a facile, green and scalable post-fabrication treatment approach, which enhanced significantly the high-rate anode performance of lithium titanate (Li4Ti5O12). Main emission lines in Ar/N2 plasma measured by optical emission spectroscopy reveal that the dominant excited high-energy species in Ar/N2 plasma are N2*, N2+, N∗ and Ar∗. Sufficient oxygen vacancies have been evidenced by high resolution X-ray photoelectron spectroscopy analysis and Raman spectra. Nitrogen doping has been achieved simultaneously by the surface reaction between pristine Li4Ti5O12 particles and chemically reactive plasma species such as N∗ and N2+. The variety of Li4Ti5O12 particles on the surface of electrodes after different plasma processing time has been examined by grazing incident X-Ray diffraction. Electrochemical impedance spectra (EIS) confirm that the Ar/N2 atmospheric plasma treatment facilitates Li+ ions diffusion and reduces the internal charge-transfer resistance. The as-prepared Li4Ti5O12 anodes exhibit a superior capacity (132 mAh g−1) and excellent stability with almost no capacity decay over 100 cycles under a high C rate (10C). Schematic diagram for the preparation of the Ar/N2 plasma-treated Li4Ti5O12 electrodes. [Display omitted] •Atmospheric pressure Ar/N2 plasma jet irradiation was used to improve the Li4Ti5O12 anodes.•Plasma ions could decrease Li4Ti5O12 particles size.•N2 plasma also could achieve nitrogen doping in Li4Ti5O12.•The plasma treated Li4Ti5O12 exhibited improved high rate capability and cycling durability.