IR Spectra and Discharge Performance of Fluorinated Bamboo Charcoals

Abstract

Li/graphite fluoride (GFx) cells have been widely noticed during the past decades due to its highest theoretical capacity, high energy density, long shelf life, safety and a wide operating temperature range in primary lithium batteries. Bamboo charcoal is cheap and widely used carbon with high specific surface area and large layer spacing, which is suitable to be fluorinated to form carbon fluoride. Five products with varied fluorine and color were obtained by fluorinating bamboo charcoal under varied reaction conditions. FT-IR spectra of these FBCs were studied. The absorbance peak related to C-F band was involved into five Gaussian peaks, and the area of each peak was calculated. The specific discharge capacity of each product was measured by galvanostatic discharging at 0.01C rate. It is turned out that there is a positive linear relationship between the specific capacity and the percentage of the peak area related to semi-covalent covalent C-F, if the carbon in the products was removed. The discharge curves showed that the discharge process could be divided into three parts. The pure compound corresponding to the first part of the discharge is the target material we actually want.