The structure and electrochemical properties of beta-Co(OH)(2) powders, synthesized by a chemical precipitation method, were investigated. The results of X-ray diffraction show that a reversible reaction between beta-Co(OH)(2) and hcp Co occurs. The cycling induces a capacity loss of beta-Co(OH)(2) electrode, which is probably attributed to the dissolution of beta-Co(OH)(2) and the subsequent formation of alpha-Co(OH)(2) and CoOOH. The results of electrochemical impedance spectra indicate that the electrochemical discharge process of the as-prepared Co(OH)(2) powders consists of three steps, namely the charge-transfer reactions of Co/CoHx and Co/Co(OH)(2), and the hydrogen diffusion within Co, depending on the depth of discharge.