N. Kurita, Molecular orbital calculations on electronic properties and lithium storage of substituted disordered carbons, MOLEC CRYST, 340, 2000, pp. 413-418
We employed a polyaromatic hydrocarbon C54H18 as a model cluster for disord
ered carbons and investigated the effect of BNB-unit substitutions on the e
lectronic and Li absorption properties of disordered carbons, by using a se
miempirical molecular orbital method. BNB substitutions prefer to occur at
the periphery of C54H18 Sheet and create electron acceptor levels in a lowe
r energy region than that for C54H18, This level accepts electrons from the
absorbed Li atoms more easily, so that the Li absorption energies for thes
e BNB-substituted C54H18 are larger than that for C54H18 The absorbed Li at
oms are stabilized near B atoms to be far from N atoms, and (BNB)(2)-substi
tuted C54H18 has smaller Li absorption energy than B2C52H18. These results;
indicate that N atoms may have a negative effect for enhancing Li-absorpti
on energy of disordered carbons.