Materials Design of Lithium Ion Rechargeable Battery by Quantum-Chemical Calculation.

Part 1. Performance Evaluation of Computational Program and Search of Carbon Cluster Model

Abstract

Recently high performance rechargeable battery for movable communicator and batteries of electric automobiles is in great demand. In order to develop higher performance lithium ion rechargeable battery, it is necessary to reveal structures and mechanism of Li absorption or intercalation into carbon electrode. But it is quite difficult to experimentally reveal those structures and mechanisms, because carbon materials are amorphous clusters. We investigated structures and mechanisms of Li absorption or intercalation into carbon clusters using ab initio molecular orbital calculation, aiming at the materials design of lithium ion rechargeable battery. Using the ab initio molecular orbital calculation program Q-Chem, we examined the result of the previous carbon model using the semi-empirical molecular orbital method by Yamabe et al., and calculated electronic energy levels on our modified carbon cluster model consisting of more than 100 carbon atoms. As a result, we found an optimum structure of carbon cluster, and succeeded in the materials design of carbon electrode of lithium ion rechargeable battery.