Construction of hygroscopic-mechanical dual-enhanced PVA/PEI/LiCl hydrogel for high-performance moisture power generation

Moisture-electric generation (MEG) hydrogels are emerging as a promising candidate for lightweight self-powered electronics by scavenging energy from atmospheric water vapor. Nevertheless, the simultaneous optimization of mechanical durability and electrical output performance remains a critical bottleneck for their practical applications. Herein, a porous poly(vinyl alcohol)/polyethylenimine/lithium chloride (PVA/PEI/LiCl) composite hydrogel is fabricated through a facile freeze–thaw strategy. The PEI-tailored three-dimensional porous structure boosts moisture adsorption and ion transport efficiency, while the dense hydrogen-bond network between PVA and PEI endows the hydrogel with superior structural stability and tensile flexibility. Moreover, the synergistic effect of PEI-induced electric double-layer behavior and LiCl-based ionic system substantially enhances ionic conduction and moisture-electric conversion capability. The optimized composite hydrogel achieves a tensile strength of 4.32  MPa and a breaking elongation of 473 %. Under 99 % relative humidity, the hydrogel exhibits a water uptake capacity of 149 % within 12  h and a high ionic conductivity of 1.19 S m −1 . The assembled MEG device yields an open-circuit voltage of ∼ 1.0  V, a short-circuit current of 713 μA, and a peak power density of 104  μW·cm −2 , alongside long-term operational stability for over 5  h without obvious performance attenuation. Furthermore, series-connected MEG devices can steadily drive commercial LEDs and digital watch. This work proposes a synergistic structural and ionic regulation strategy to synchronously improve the mechanical robustness and moisture-electric performance of hydrogels, providing a feasible avenue for the design of high-performance MEG materials and advanced self-powered electronic systems.