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

Atmospheric pressure Ar/N-2 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/N-2 plasma measured by optical emission spectroscopy reveal that the dominant excited high-energy species in Ar/N-2 plasma are N-2*, N-2(+), 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 N-2(+) 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/N-2 atmospheric plasma treatment facilitates Li+ ions diffusion and reduces the internal charge-transfer resistance. The asprepared 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). (C) 2014 Elsevier B.V. All rights reserved.