Bicontinuous‐Phase Network Interface Engineering for Stabilizing Anodes in Flexible Aqueous Zinc‐Ion Batteries

Aqueous zinc (Zn)‐ion batteries (AZIBs) are attractive for flexible energy‐storage devices because of their intrinsic safety, low cost, and environmental compatibility. However, Zn metal anodes (ZMAs) suffer from dendrite growth, hydrogen evolution, corrosion, byproduct accumulation, and uneven deposition during repeated plating/stripping and mechanical bending, which limit their long‐term stability and practical application. Here, a bicontinuous interfacial film, denoted SPI, is constructed on ZMAs to improve interfacial stability through combined ion‐transport regulation and mechanical protection. The zincophilic –SO ₃ H groups in SPI preferentially interact with Zn ²⁺ , forming uniform ion‐transport pathways that homogenize Zn ²⁺ flux and promote even Zn deposition. Meanwhile, the polyimide component provides mechanical strength and structural stability, suppressing dendrite penetration and maintaining interfacial integrity during prolonged cycling. Benefiting from these synergistic effects, the SPI‐modified Zn || Zn symmetric cell operates stably for over 800 h at 5 mA cm ⁻² and 5 mAh cm ⁻² with low voltage polarization. In Zn || MnO ₂ full cells, the SPI‐modified anode enables 85% capacity retention after 700 cycles at 1 A g ⁻¹ . Moreover, SPI reduces stress concentration and uneven deposition under bending, allowing flexible pouch cells to power an electronic timer in different bent states.