A novel 1 V battery composed of Sn-LiCoPO4 using aqueous lithium hydroxide electrolyte is described. Reversible extraction and insertion of lithium from and into the divine type LiCoPO4 is reported. The electrochemical behavior of the Sn-LiCoPO4 battery was analyzed using charge/discharge cycling and cyclic voltammetry. Sn-LiCoPO4 battery exhibited charge/discharge voltages of 1.3 V/0.8 V versus Sn with a reversible capacity of 80 mAh/g. The structural and morphological changes of LiCoPO4 particles before and after electrochemical measurements Were investigated by X-ray diffraction (XRD) and transmission, electron microscopy. XRD data showed that extraction of lithium proceeds via at least a two-phase mechanism with LiCoPO4 and CoPO4 phases. Upon lithium reinsertion crystalline LiCoPO4 was formed. The cell voltage indicated these batteries were not completely charged, forming single-phase CoPO4 material. Energy-dispersive X-ray analysis coupled with transmission electron microscopy confirmed the chemical quality of the charged and discharged LiCoPO4 in terms of crystallinity and elemental distribution.