Recent development of carbon materials for Li ion batteries

Lithium ion secondary batteries are currently the best portable energy storage device for the consumer electronics market. The recent development of the lithium ion secondary batteries has been achieved by the use of selected carbon and graphite materials as an anode. The performance of lithium ion secondary batteries, such as the charge/discharge capacity, voltage profile and cyclic stability, depend strongly on the microstructure of the anode materials made of carbon and graphite. Due to the contribution of the carbon materials used in the anode in last five years, the capacity of the typical Li ion battery has been improved 1.7 times. However, there are still active investigations to identify the key parameters of carbons that provide the improved anode properties, as carbon and graphite materials have large varieties in the microstructure, texture, crystallinity and morphology, depending on their preparation processes and precursor materials, as well as various forms such as powder, fibers and spherule. In the present article, we describe the correlation between the microstructural parameters and electrochemical properties of conventional and novel types of carbon materials for Li ion batteries, namely, graphitizable carbons such as milled mesophase pitch-based carbon fibers, polyparaphenylene-based carbon heat-treated at low temperatures and boron-doped graphitized materials, by connecting with the market demand and the trends in Li ion secondary batteries. The basic scientific theory can contribute to further developments of the Li ion batteries such as polymer batteries for consumer electronics, multimedia technology and future hybrid and electric vehicles. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.