摘要
Atmospheric pressure Ar/N 2 plasma jet irradiation through carbon working electrode is applied into the manufacturing process to improve electrochemical performance of commercial Li 4 Ti 5 O 12 electrode. The rate capability is significantly enhanced due to plasma treatment. Plasma emission spectra is measured by optical emission spectroscopy, showing typical nitrogen band, argon band and C 2 , CN lines. Morphology and elemental mapping are characterized by scanning electron microscope, transmission electron microscope, and electron probe micro-analyzer. The compact carbon species can be observed clearly, and the pores can be filled by nanocarbon, forming complete conducting network. The chemical states are confirmed by X-ray photoelectron spectroscopy, providing the evidence of nitrogen bonding with carbon. The properties of carbon are also confirmed by Raman spectra. These features are reflected to better electrochemical performances and electrochemical impedance spectroscopy results. The plasma treated sample exhibits a superior capacity and excellent stability with almost no capacity decay at high charging rate (10 C) after 300 cycles.