An Intrinsically Self‐Healing NiCo||Zn Rechargeable Battery with a Self‐Healable Ferric‐Ion‐Crosslinking Sodium Polyacrylate Hydrogel Electrolyte

Self-healing solid-state aqueous rechargeable NiCo||Zn batteries are inherently safe and have a high energy density and mechanical robustness. However, the self-healability of solid-state batteries has only been realized by a few studies in which electron/ion-inactive self-healable substrates are utilized. This arises from the lack of self-healable electrolytes. Now an intrinsically self-healing battery has been designed that utilizes a new electrolyte that is intrinsically self-healable. Sodium polyacrylate hydrogel chains are crosslinked by ferric ions to promote dynamic reconstruction of an integral network. These non-covalent crosslinkers can form ionic bonds to reconnect damaged surfaces when the hydrogel is cut off, providing an ultimate solution to the intrinsic self-healability problem of batteries. As a result, this NiCo||Zn battery with this hydrogel electrolyte can be autonomically self-healed with over 87 % of capacity retained after 4 cycles of breaking/healing.