Improvement of the electrochemical properties of Li/CFx primary batteries induced by Nitrogen plasma treatment from silica and carbon fluoride

Abstract

The electrochemical properties of a CF_X cathode were improved by defluorination of the surface with a N₂ plasma and using a silica wafer. Compared to the N₂ plasma treatment alone, when the CF_X and silica were reacted together, the C-F bonds were modified and the surface was etched efficiently, so defluorination was enhanced. An electrochemical analysis confirmed that Half-cells prepared by treating CFx and silica with nitrogen plasma exhibited a capacity of about 400 mAh/g at 5C. In addition, it was confirmed that the loss of charge transfer was reduced by up to 71% compared to that for pristine CF_X. As shown by a GITT analysis, when the CFx and silica were treated with N₂ plasma together, the ion conductivity gradually increased due to a decrease in the ion diffusion barriers and the formation of a carbon layer. Therefore, this is a simple and effective way to improve the conductivities of CF_X cathode materials with the energy of a N₂ plasma and the silica-fluorine reaction.