Regulating the coordination environment of H2O in hydrogel electrolyte for a high-environment-adaptable and high-stability flexible Zn devices

From frigid polar nights to sweltering desert days, powering flexible electronics in extreme environments remains a daunting challenge. Aqueous zinc-ion batteries have long been considered promising for safe, low-cost, and sustainable energy storage, yet they still struggle with zinc dendrite growth, hydrogen evolution, corrosion, and severe performance loss at low temperatures. Now, a research team led by scientists from the Harbin Institute of Technology, the University of Adelaide, and Jiangmen Laboratory of Carbon Science and Technology has unveiled a breakthrough: a high-environment-adaptable hydrogel electrolyte (HEA-3) that precisely regulates the coordination environment of water molecules. Published in Nano-Micro Letters, this work—led by Prof. Zhixin Tai and Prof. Yajie Liu—demonstrates a new pathway for creating flexible zinc-based devices that operate reliably from room temperature down to –70 °C.

Why HEA-3 Matters

• Extreme Temperature Tolerance: Maintains high ionic conductivity (4.12 × 10^-3 S cm^-1) at –50 °C, with stable cycling even at –70 °C.
• Exceptional Reversibility: Zn||Cu cells achieve 99.4% coulombic efficiency over 900 cycles; Zn||Zn symmetric cells run for over 1,700 hours without dendritic failure.
• Long-Life Flexibility: Flexible Zn||PANI devices deliver more than 30,000 cycles at –40 °C, retaining capacity under folding, twisting, and freezing conditions.

Innovative Design and Mechanisms

• Hydrogel Coordination Engineering: A cross-linked polymer matrix of polyacrylamide (PAM), carboxymethyl cellulose (CMC), and ethylene glycol (EG) disrupts continuous hydrogen-bond networks among water molecules. This reduces proton mobility, suppresses hydrogen evolution, and prevents zinc corrosion.
• Molecular-Level Optimization: DFT and molecular dynamics simulations confirm water molecules preferentially bind with EG, CMC, and PAM rather than with each other, stabilizing a reconstructed multi-hydrogen-bond network.
• Structural Strength and Ionic Transport: The semi-interpenetrating network enhances mechanical durability while interconnected pore channels facilitate uniform Zn²⁺ transport, yielding a high Zn²⁺ transference number (0.89) and smooth, dendrite-free zinc deposition.

Applications and Future Outlook

• Wearable Energy Storage: The flexible Zn||PANI device operates under extreme bending and twisting, maintaining over 85% capacity after 1,000 bending cycles—ideal for smart textiles, portable sensors, and medical wearables.
• Cold-Climate Electronics: Stable performance at ultra-low temperatures opens doors for aerospace, polar research, and defense applications.
• Grid-Scale Storage: By mitigating dendrites and corrosion across a wide temperature range, HEA-3 electrolytes could boost the safety and lifespan of large-scale zinc-based energy storage systems.

Looking ahead, the team envisions expanding this water coordination regulation strategy to other metal-ion systems, exploring new polymer frameworks and stimuli-responsive functionalities. This work marks a decisive step toward creating flexible, high-stability, all-weather energy storage devices ready to perform where conventional batteries cannot.

Stay tuned for further breakthroughs as the researchers continue to redefine the limits of aqueous zinc battery technology.