A proton conductor gel polymer electrolyte based on hydroponics gels (HPG) mixed with 10 M ammonium nitrate (NH4NO3) was found to yield a very high electrical conductivity of 0.60 S cm(-1). The optimized composition, i.e., the HPG-10 M NH4NO3, was then used in our proton battery to make a Zn + ZnSO4 center dot 7H(2)O/HPG-10 M NH4NO3/MnO2 system. The open-circuit voltage of the battery was 1.42 V during 24 h of storage. The battery obtained a capacity of 14.67 mAh and a maximum specific energy of 18.96 mW cm(-2). (c) 2007 The Electrochemical Society.