Zincophilic Cu/flexible polymer heterogeneous interfaces ensuring the stability of zinc metal anodes

Aqueous zinc-ion batteries are regarded as promising electrochemical energy-storage systems for various applications because of their high safety, low costs, and high capacities. However, dendrite formation and side reactions during zinc plating or stripping greatly reduce the capacity and cycle life of a battery and subsequently limit its practical application. To address these issues, we modified the surface of a zinc anode with a functional bilayer composed of zincophilic Cu and flexible polymer layers. The zincophilic Cu interfacial layer was prepared through CuSO₄ solution pretreatment to serve as a nucleation site to facilitate uniform Zn deposition. Meanwhile, the polymer layer was coated onto the Cu interface layer to serve as a protective layer that would prevent side reactions between zinc and electrolytes. Benefiting from the synergistic effect of the zincophilic Cu and protective polymer layers, the symmetric battery exhibits an impressive cycle life, lasting over 2900 h at a current density of 1 mA·cm⁻² with a capacity of 1 mA·h·cm⁻². Moreover, a full battery paired with a vanadium oxide cathode achieves a remarkable capacity retention of 72% even after 500 cycles.