Anode Performance of B-doped Mesophase Pitch-based Carbon Fibers in Lithium Ion Secondary Batteries

Abstract

Mesophase pitch-based carbon fibers (MPCF) have been prepared by a melt-brow method and applied to Li ion secondary battery. To improve the reversible capacity, B was doped to the fiber about 1 at % by adding B4C to the pre-carbonized milled fibers and then heat-treated up to 3000°C in Ar. The structure of B-doped fibers was characterized and compared with that of non-doped standard fibers, and also anode performances for Li ion battery were evaluated. The capacity of B-doped fibers was 340 mAh/g, while the non-doped fiber showed 300 mAh/g. The voltammograms of both fibers were different from each other. The mechanism of anode reaction is discussed based on the unique structure of B-doped fibers. It is suggested that B doping to the MPCF is very effective for the anode performance.