First-Principles Study of an Ethoxycarbonyl-Based Organic Electrode Material of Lithium Battery

摘要

Organic molecules are potential candidates for electrode materials of rechargeable lithium batteries because of their beneficial properties such as cost-effective, environmentally friendly, and sustainable. Until now, the efficient theoretical method to study the organic electrode materials remains elusive. In this paper, an organic electrode material of a lithium battery, Li2C_(80)O8H_(12)·H2O, is investigated by the dispersion-corrected density functional theory method. Two outlined points are presented: (1) the method is a powerful tool to predict the geometry structure and the discharge potential of the organic electrode material; and (2) the periodic crystal structure does more to determine the property of the organic electrode material than the single molecular structure. The intermediate structure corresponding to the first discharge plateau is explored, in which the reversible inserted Li ion occupying layers and the unoccupying layers are arranged alternatively. The special structure makes the intermediate state have a closed-shell electron configuration and lowers the electron kinetic energy on the Fermi level of the system. The band gap is about 1.0 eV, which means that the organic electrode material has a good electron conductivity.