Anti-freezing, mechanically robust polyelectrolyte hydrogels cross-linked with natural phytic acid for high-performance flexible solid-state supercapacitors
摘要
As promising candidates for next-generation wearable electronics, flexible supercapacitors demand electrolyte materials combining high ionic conductivity with environmental adaptability. While hydrogels have emerged as attractive electrolytes due to their intrinsic flexibility and tunable physicochemical properties, conventional systems face critical challenges including compromised ionic conductivity and poor freeze resistance. Herein, we develop a polyelectrolyte hydrogel through rational molecular design using phytic acid (PA) as a multifunctional cross-linker. The dual-functional synergy between PA's six phosphate groups (enhancing ionic hydration networks) and LiCl (facilitating ion dissociation) enables exceptional ionic conductivity (7.17 S m⁻1) alongside mechanical robustness (1.3 MPa tensile strength at 1145% strain). Notably, the coordinated hydration effects impart remarkable freeze resistance, maintaining 82% conductivity at − 20 °C. When integrated with MXene/PANI symmetric electrodes, the resulting solid-state supercapacitor achieves record-breaking performance: high areal capacitance (229.7 mF cm−2 at 1 mA cm−2), outstanding cycling stability (88.8% capacitance retention after 8500 cycles), and operational reliability across extreme conditions. This strategy opens new avenues for designing adaptive energy storage systems compatible with harsh-environment wearable applications.
Graphical abstract