Electrochemical Property of Solid-State MnO2-Zn Battery with the Combination of Improved Cathode and Solid Electrolyte

Aqueous zinc-ion batteries (ZIBs) are a promising technology that can satisfy the present requirements for battery systems because of their excellent characteristics (e.g., low cost, recurrent availability of zinc metal resources, high chemical/physical stability, and safety). However, the growth of zinc dendrites in alkaline electrolytes makes ZIBs unsuitable for many applications. To address this problem, we developed a novel ZIB using a solid-state electrolyte based on polyacrylamide hybridized with layered double hydroxide (PAM-LDH). The hydrogel electrolyte exhibited an excellent ionic conductivity. The result also indicates that a PAM-LDH electrolyte combined with NH 4 F-treated MnO 2 shows an ultra-high capacity of 354.3 mAh g −1 at a current density of 0.1 A g −1 and an energy density of 484.3 Wh kg −1 at a peak power density of 136 W kg −1 (based on the weight of the cathode). Moreover, the cycle retention of the cell was significantly improved to 88.8% after 1000 cycles compared with that of the untreated MnO 2 /PAM-LDH/Zn cell (79.5%). These results demonstrate that F − -doped cathode and hydrogel electrolyte can form the foundation for practically usable solid-state ZIBs.