Ultra-stable and dendrite-free Zn anodes via a self-regulating sodium alginate-zinc phosphate hybrid interface for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) suffer from dendrite growth and side reactions, which severely limit their stability and commercialization. To address these issues, we developed a novel self-regulating hybrid interfacial layer composed of sodium alginate (SA) and in-situ formed zinc phosphate (ZP), which effectively regulates Zn 2+ flux and promotes uniform deposition. Specifically, SA coordinates with Zn 2+ through carboxyl groups to buffer local ion accumulation, while ZP improves ionic conductivity to facilitate rapid and uniform Zn 2+ transport. The synergistic interface mitigates interfacial ion concentration gradients and promotes homogeneous nucleation and lateral Zn growth, resulting in preferential (002)-oriented deposition and effective dendrite suppression. Therefore, the modified Zn anode demonstrates exceptional cycling stability, operating stably for >3000 h at 1 mA cm −2 and 1 mAh cm −2 , and maintains stable performance exceeding 3050 h at 5 mA cm −2 . This work proposes a scalable and eco-friendly interfacial strategy for stabilizing Zn anodes and highlights the potential of Zn 2+ flux modulation in advancing practical AZIBs.