Multifunctional polyoxometalate-based conductive hydrogels for low temperature tolerant, flexible wearable electronics
Flexible wearable electronics require materials that simultaneously exhibit high conductivity, mechanical flexibility, and environmental robustness. Polyoxometalate (POM)-based conductive hydrogels are promising candidates but suffer from poor interfacial compatibility with polymer matrices and severe conductivity loss at subzero temperatures. Here, we report a POM-based proton-conductive hydrogel (PVA/P(SBMA-AM)/PW12/PA, denoted PSAWA) engineered by incorporating zwitterionic sulfobetaine methacrylate (SBMA), phytic acid (PA), and H3PW12O40 (PW12) into a poly(vinyl alcohol)-polyacrylamide dual-network. SBMA enhances PW12 loading and dispersion via an electrostatic–steric synergistic mechanism, while PA cooperates with PW12 to construct low-energy-barrier proton-conduction pathways, enabling fast proton migration even at −40 °C. The resulting PSAWA hydrogel achieves ultrahigh proton conductivities of 2.71 × 10−1 S cm−1 at 25 °C and 1.06 × 10−2 S cm−1 at −40 °C, alongside high stretchability, self-healing capability, antibacterial activity, and biocompatibility. Flexible biosensors and supercapacitors fabricated from PSAWA maintain outstanding performance at −40 °C. This work provides a viable strategy for developing low-temperature-tolerant proton-conductive hydrogels for advanced wearable electronics.