A new composite consisting of a mixture of zinc and hydrated ammonium zinc sulfate, Tutton salt, has been elaborated and studied as anode material for all-solid state protonic cells. The results obtained point out the ability of (NH4)2Zn(SO4)2·6H2O double salt to concomitantly exchange protons with the solid proton conducting electrolyte and accommodate Zn2+ cations issued from oxidation. Such features have been evinced by thermal and crystallographic characterizations. The anode composition has been optimized through a kinetic study on a three-electrode type-cell, showing that a 35wt.% salt-based composite displays the minimum polarization. Zn/MnO2 cells prepared using such a composite anode achieve relatively high specific capacity and energy of, more than 30Ahkg−1 and 40Whkg−1, respectively.