TITANIC ACID COMPOUND, PROCESS FOR PRODUCING THE TITANIC ACID COMPOUND, ELECTRODE ACTIVE MATERIAL CONTAINING THE TITANIC ACID COMPOUND, AND STORAGE DEVICE USING THE ELECTRODE ACTIVE MATERIAL

摘要

This invention provides a titanic acid compound-type electrode active material having a high battery capacity and, at the same time, having excellent cycle characteristics. The titanic acid compound exhibits an X-ray diffraction pattern corresponding to a bronze-type titanium dioxide except for a peak for a (003) face and a (-601) face and having a lattice spacing difference between the (003) face and the (-601) face, i.e., d(003) - d(-601), of not more than 0.0040 nm. The titanic acid compound may be produced by reacting a layered alkali metal titanate, represented by a compositional formula MxM'x/3Ti2-x/3O4 wherein M and M', which may be the same or different, represent an alkali metal; and x is in the range of 0.50 to 1.0, with an acidic compound and then heating the reaction product at a temperature in the range of 250 to 450°C.