LITHIUM INSERTION CHARACTERISTICS OF CUNB2O6

Chemical and electrochemical lithium intercalation reactions of CuNb2O6 with a columbite structure were examined. The chemical lithiation by n-butyllithium occurred accompanied by the formation of a new phase, LixCuNb2O6 (0 less than or equal to x less than or equal to 1.9), with an apparent crystal lattice. The a axis of the new phase is a little longer (0.6 Angstrom) than that of the parent phase. The electrochemical cell potential of Li/CuNb2O6 almost attained a plateau at 2.6 V against Li/Li+ in the range from x = 0.1 to x = 1.0 in LixCuNb2O6, corresponding to the reduction from Cu2+ to Cu+. The reduction behavior in the range from x = 1.0 to x = 1.9 suggested the reduction from Nb5+ to Nb4+. (C) 1995 Academic Press, Inc.