USE OF A SUPERFINE EXPANDED GRAPHITE AND PREPARATION THEREOF

摘要

This application relates to the use of an expanded graphite material prepared by adding C1F3 in liquid form to solid carbon, by heating the mixture at a reaction temperature between 22 to 100°C to form intercalated compounds of the formula C2F.xC1F3 and C1Fgas with the C2F being a solid material present in layers and the C1F3 being a gaseous material present between adjacent layers of C2F, according to the reaction C (solid) + (x+1/2) C1F3 (liquid) ? C2F.xC1F3 (solid) +1/2C1F(gas). The method further comprises the step of subsequently heating the intercalated compound to expel the C1F3 gas and to simultaneously form CF4 gas, with the gas formation and expulsion serving to expand the structure formed by the C2F layers, with the C2F layers changing composition to carbon layers with a percentage of fluorine in the range up to 5 %, said heating temperature lying in the range from 400 to 500°C. Such an expanded graphite material is particularly useful in electrochemical devices, e.g as an anode in a lithium ion battery or as a catalyst support.