Multifunctional PVA/MXQDs hydrogels for integrated flexible strain sensing and solid-state energy storage systems

, together with good cycling stability, retaining 70% of its initial capacitance after 5000 charge-discharge cycles. Furthermore, the incorporation of copper nanowires significantly improves the electrical conductivity and stretchability of the hydrogel, yielding an elongation at break of up to 244%. When applied as a strain sensor, the hydrogel demonstrates excellent linearity, a wide operational strain range exceeding 60%, high durability over 300 loading-unloading cycles, and high strain sensitivity with a gauge factor of 3.50. In addition, the hydrogel-based sensor enables accurate monitoring of various human motions, including arm bending, finger motion, and throat movement. Collectively, these results highlight the strong potential of the proposed multifunctional hydrogel as an integrated platform for flexible energy storage and wearable sensing applications.