The fabricated PANa hydrogel has the following advantages. First, the PANa absorb and retain variable contents of water and free-moving ions, thus tuning the ionic conductivity. Second, the vast absorption of optimized 6 M KOH+0.2 M Zn(CH3COO)₂ ensures its intrinsically good ionic conductivity and low viscosity. Third, the PANa polymer chains provide sufficient acrylate ions at the interface between electrolyte and Zn anode, facilitating the formation of quasi-SEI during initial cycles. Advantageously, this may eliminate zinc dendrites which were prevalent in aqueous and PVA-based electrolytes. These synergistic effects mentioned above may improve the battery performance by enhancing the high capacity and ultra-cycling stability observed from both Zn//NiCo and Zn-air batteries by the use of the polyelectrolyte in accordance with the embodiments of the present invention.

In an exemplary fabrication process, a concentrated sodium hydroxide solution (27 mL, 25 M) is slowly dropped in an aqueous solution of acrylic acid monomers (54 mL, 47 wt. %) in 12 hours. Prior to use, the acrylic acid monomer was purified by distillation under reduced pressure and stored in a refrigerator. Ammonium persulfate (0.78 g) was then added into the neutralized solution and stirred for 0.5 h at room temperature. After the magnetic stirring, the solution was degassed and sealed under N2 to remove the dissolved oxygen. Next, free-radical polymerization was allowed to proceed at 40° C. for 30 h. Finally, the as-prepared polymer was fully dried at room temperature and then soaked in a mixed solution (500 mL) of zinc acetate (0.2 M) and potassium hydroxide (6 M) up to one week to achieve the equilibrated state.