High-performance green moisture-electric generator based on supramolecular hydrogel with tens of milliamp electricity toward practical applications

Abstract

Scavenging sustainable energy from moisture has emerged as a promising green technology to achieve carbon neutrality in next-generation energy suppliers. Besides, ecofriendly materials used for moisture-electric generators (MEGs) can add significant contributions to alleviate carbon emission. Until now, it is still a grand challenge for MEGs as a direct power supply for practical applications due to low power density and intermittent electric output. Herewith, we design a green MEG with high direct-current (DC) power output by introducing polyvinyl alcohol-sodium alginate based supramolecular hydrogel as active material. A single unit can generate an enhanced power density of up to 0.11 mW cm− 2, a milliamp-scale short-circuit current density of ca. 1.31 mA cm− 2 and an open-circuit voltage of ca. 1.30 V under moisture stimuli and room temperature. Such outstanding electric generation is mainly attributed to enhanced moisture absorption and remained water gradient to initiate ample dissociable ions transport within supramolecular hydrogel network by theoretical calculation and experiments. Of practical importance, a record-breaking enlarged current of ca. 65 mA is achieved by an integrated MEG bank with parallel connection. The high-power-output and scalable MEGs offer sufficient energy to directly power many commercial electronics in real-life scenarios, such as charging smart watch, illuminating a household bulb, driving a digital clock for one month. This work broadens the application paradigm of MEGs and provides new insight for constructing green, high-performance and scalable MEGs as sustainable energy source for Internet-of-Things and wearable applications.

High‐Performance Fully Stretchable Moist‐Electric Generator

“…[33] Tao et al investigated that an MEG prepared by PVA-sodium alginate ionic hydrogel can generate 2000 times higher output current than non-ionic PVA hydrogel MEG due to the distinct moisture uptake capability of the ionic hydrogel. [34] However, the fully stretchable capability has not yet been achieved in hydrogel-based MEG systems, and the mechanism of the excellent moist-electric generation performances of hydrogel-based MEGs is not well explored.…”