Ionic Hydrogel for Efficient and Scalable Moisture‐Electric Generation

Abstract The progress of spontaneous energy generation from ubiquitous moisture is hindered the low output current and intermittent operating voltage of the moisture‐electric generators. Herein a novel and efficient ionic hydrogel moisture‐electric generator (IHMEG) is developed by rational combination of poly(vinyl alcohol), phytic acid, and glycerol‐water binary solvent. Thanks to the synergistic effect of notable moisture‐absorption capability and fast ion transport capability in the ionic hydrogel network, a single IHMEG unit of 0.25 cm 2 can continuously generate direct‐current electricity with a constant open‐circuit voltage of ≈0.8 V for over 1000 h, a high short‐current density of 0.24 mA cm −2 , and power density of up to 35 µW cm −2 . Of great importance is that large‐scale integration of IHMEG units can be readily accomplished to offer a device with voltage up to 210 V, capable of directly driving numerous commercial electronics, including electronic ink screen, metal electrodeposition setup, and light‐emitting‐diode arrays. Such prominent performance is mainly attributed to the enhanced moisture‐liberated proton diffusion proved by experimental observation and theoretical analysis. The ionic hydrogel with high cost‐efficiency, easy‐to‐scaleup fabrication, and high power‐output opens a brand‐new perspective to develop a green, versatile, and efficient power source for Internet‐of‐Things and wearable electronics.