Nb2O5 powder was prepared by heating niobium hydroxide in the temperature range from 600 to 1000°C. The crystal system of Nb2O5 compounds depended on the heating temperatures, i.e., hexagonal, orthorhombic and monoclinic Nb2O5 compounds were obtained at 600, 800 and 1000°C, respectively. Electrochemical lithium intercalation into the three Nb2O compounds was investigated in a cell with an LiClO4-propylene carbonate electrolytic solution for the application as lithium battery cathodes. As a result, they displayed good charge-discharge performance as the cathode of 2 V class-lithium battery, which will play important role in power supply for IC memory backup developed recently. The thermodynamics and kinetics of the lithium intercalation into the Nb2O5 cathode have been investigated. The thermodynamic parameters, such as standard free energies, lithium partial molar entropy, interaction energies between ions, the crystal lattice parameters, and the kinetic parameters, such as chemical and self diffusion constants, have been obtained as a function of x-value in LiNb2O5.