LAYERED-STRUCTURE BC2N AS A NEGATIVE ELECTRODE MATRIX FOR RECHARGEABLE LITHIUM BATTERIES

A new compound with graphite-like structure, BC2N, has been synthesized by a vapor-phase reaction of acetonitrile (CH3CN) and borontrichloride (BCl3). The electrochemical behavior of BC2N was investigated in propylene carbonate (PC)-based solutions containing lithium (Li) salts. Cyclic voltammetric curves of the BC2N electrode showed current increases during the cathodic potential scans and corresponding peaks at ca. 1.5 V in the anodic scans. The cathodic currents were accompanied by electrochemical intercalation of Li from the electrolyte, and the anodic peaks resulted from the deintercalation of Li from the BC2N electrode. The polarization behavior of Li with the BC2N matrix depended on the solvent as well as the salt of the electrolytic solution. The coulombic efficiency for charge/discharge cycling under a constant current was 90% or higher in LiClO4/PC. The results indicate that BC2N is usable as a negative electrode matrix for rechargeable Li batteries.