Rechargeable proton batteries have been fabricated with the configuration Zn + ZnSO4 . 7H(2)O//solid-state proton conductor//C+ electrolyte + intercalating PbO2 + V2O5. The solid-state proton conductor is phosphotungstic acid (H3PW12O40 . nH(2)O) or a H3PW12O40 . nH(2)O + Al-2(SO4)(3) . 16H(2)O composite. The maximum cell voltage is similar to 1.8 V at full charge. The cell can run for more than 300 h at low current drain (2.5 mu A cm(-2)). Further, the cell can withstand 20 to 30 cycles. The addition of a metal hydride in the anode side enhances the rechargeability and the addition of a small amount of Al-2(SO4)(3) . 16H(2)O in the H3PW12O40 . nH(2)O electrolyte improves the performance of the battery.