Closed-loop Recyclable and Robust Supramolecular Hydrogel Electrolytes With High Zinc Ion Mobility for Stable Zinc Anode.

Hydrogel electrolytes are promising candidates for zinc-based energy storage systems (ZESs) owing to their superior safety features, favorable ionic conductivity and interfacial compatibility. However, current hydrogel electrolytes suffer from weak mechanical strength, low Zn2+ transference numbers, causing Zn dendrite growth and parasitic reactions, while the common permanent covalent crosslinked polymer matrices are non-recyclable. Herein, a supramolecular hydrogel electrolyte that achieves robust mechanical rigidity with high Zn2+ mobility is developed by introducing guanylate quadruplex (G-quadruplex), which effectively regulates concentration gradients and confines water activity. Experimental characterizations and theoretical simulations display that the G-quadruplex polyanionic network restrains water activity, homogenizes Zn2+ flux and uniforms electric field, effectively stabilize the Zn anode. The hydrogel electrolyte enables durable cycling life of 3,800 hours at 1 mA cm-2 and 1,800 hours at 10 mA cm-2 in Zn//Zn symmetric cells. Additionally, the zinc-ion hybrid supercapacitors display outstanding electrochemical performance and high safety, achieving 97.4% capacity retention over 10 000 cycles. Moreover, the wasted supramolecular hydrogel can be facilely depolymerized back into monomers and biomacromolecules with negligible performances loss, underscoring its recyclability advantage over conventional covalently crosslinked hydrogels. This work provides a supramolecular engineering strategy that overcomes the trade-offs in hydrogel electrolytes, advancing sustainable and durable ZESs.