Porous chitosan–SiO2 membranes were prepared by ultrasonic mixing solution-cast and porogen removal method at different SiO2 weight ratios. To remove SiO2 from chitosan membranes, NaOH solution was used to dissolve SiO2. Porous chitosan:SiO2 membrane with the weight ratio 1:2 produced optimum average pore size (8.5 μm) with an amorphous structure and the highest water uptake (257.1%). Further soaking of this membrane in NH4CH3COO electrolyte solution for two days produced the highest conductivity (3.6×10−3 S cm−1) and optimum breakdown voltage (1.8 V). Fabrication of coin cell proton battery displayed an open circuit potential of 1.5 V for 7 days, maximum power density (6.7 mW cm−2) and small current resistance (0.03 Ω). The specific discharge capacities obtained from discharge profile of 39.7 mA h g−1 (0.5 mA) and 43.8 mA h g−1 (1.0 mA) increased as the discharge currents were increased. These results showed that a porous chitosan–SiO2 membrane is suitable membrane for the proton batteries.