Selective Zn-ion channels enabled by a double-network protective layer for stable zinc anode

The development of rechargeable aqueous zinc-ion batteries (AZIBs) is restricted by inevitable dendrite growth and detrimental parasitic reactions occurred on the Zn metal anode. To address these intractable issues, we constructed a double-network agarose-polyacrylamide (AG-PAM) gel on Zn anode to form an eco-friendly and protective solid-electrolyte interphase layer. Owing to facilitating the desolvation of [Zn(H2O)6]2+ clusters and homogenizing zinc ions flux through selective Zn2+ tunnel, the artificial AG-PAM double-network hydrogel not only inhibited irreversible parasitic reactions but also enabled dendrite-free Zn accumulation. As a result, AG-PAM/Zn||AG-PAM/Zn symmetric cells could deliver an ultralong cycling lifespan over 3500 h at 1 mA cm−2/1 mA h cm−2. Moreover, AG-PAM/Zn||Zn0.09Mg0.09V2O5 full cells presented enhanced cycling stability with the capacity of 240.8 mA h g−1 after 250 cycles at 1 A g−1, in contrast to rapidly failure of bare Zn full cells after 100 cycles. This double-network hydrogel protection strategy will grasp new insight into Zn-anode design for safe aqueous batteries construction in future.