Anode properties of calcite-type MBO3 (M: V, Fe)

V(III) was substituted in place of Fe(III) in the calcite FeBO3 matrix to reduce the charge/discharge voltage and increase the theoretical capacity. The mean charge/discharge voltage of the calcite VBO3 was 1 V lower than that of FeBO3, and the reversible capacity was 420 mAh/g. To investigate the characteristics of borate anodes, the X-ray Rietveld, XPS and XAFS profiles were measured. To further improve the anode performance of VBO3, a carbon coating using a naphthalene-based isotropic pitch with a low-temperature softening point was applied. (C) 2003 Elsevier Science B.V. All rights reserved.