Solvent-Mediated Microphase Separation in Ionogels for the Construction of Mechanically Robust and High-Energy-Output Moisture-Electric Generators

Abstract

The rational design of mechanically robust gel-based moisture-electric generators (MEGs) with broad environmental adaptability is of great significance for the construction of self-powered wearable systems, addressing critical challenges in sustainable energy harvesting for practical applications. In this study, we report a high-energy-output MEG based on a microphase-separated double-network ionogel, which contains a physically crosslinked polyvinyl alcohol network, chemically crosslinked poly(2-acrylamido-2-methylpropanesulfonic acid) and hygroscopic ionic liquid (BMIMCl). The introduction of ionic liquids leads to microphase separation, resulting in the formation of a solvent-rich phase and a polymer-rich phase within ionogels. In this structure, the solvent-rich phase facilitates stretching and ionic conduction, whereas the polymer-rich phase contributes to the improvement of mechanical strength. The resultant ionogels demonstrate exceptional mechanical robustness featuring a tensile strength of 4.63 MPa, 501.02% elongation at break, 10.81 MJ m⁻³ fracture toughness, and < 5% hysteresis. More importantly, benefit from the intrinsic wide-temperature tolerance of ionic liquids, the ionogel-based MEGs can operate over a wide humidity (30%–90% relative humidity) and temperature range (−25°C to 55°C), delivering a stabilized output voltage of 0.9–1.25 V and a record short-circuit current density of 539.42 µA cm⁻², outperforming most reported gel-based MEGs. The electricity generation arises from synergistic coupling of humidity-gradient-driven H⁺ migration (major output current contribution) and Al electrode oxidation (major output voltage contribution). Through modular integration, 50 series-connected units achieved an output of up to 60 V, directly powering commercial electronics, such as smartwatches and calculators. This finding provides a feasible strategy for designing all-weather, mechanically robust, and scalable self-powered systems.

Keywords

flexible electronic devices / ionogels / mechanically robust / microphase separation / moisture-electric generators

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2025 The Author(s). Interdisciplinary Materials published by Wuhan University of Technology and John Wiley & Sons Australia, Ltd.