Oil-furnace Carbon Black as the Negative Electrode Material for Lithium Secondary Batteries

Abstract

As a possible negative electrode material for lithium secondary cells, various carbon black (CB) samples prepared by the oil-furnace process and having different microscopic structures were investigated in an LiClO4-ethylene carbonate/dimethoxyethane (1/1 by volume) solution. CB samples were characterized by the average particle size (dn), the BET specific surface area (SN2), the amount of dibutylphtalate absorption and the micropore volume (Vm, mercury porosimetry). The irreversible capacity at the initial reduction stage increased with incresing SN2, that is, coarse elementary particles led to small irreversible capacity. There were two couples of redox processes in a cyclic voltammogram. With increasing Vm, the anodic peak current at around 0.2V became larger, whereas that at 0.9V remained constant. The intercalation/deintercalation of Lithium into/from layer-structured portion of CB material was considered to take place at 0-0.2V mainly at the neck position connecting two elementary particles.