Nanophase-Separation Heterogel Photoiontronics for Bidirectional Ion-Gradient Energy Conversion Modulation.

Abstract

Current light-responsive reverse electrodialysis systems within the salinity difference enhance the ion-gradient energy conversion efficiency by modulating the chemical potential gradient. However, the monotonic amplification of chemical potential gradient leads to the unidirectional enhancement of energy output and risk excessive energy release. Here, we present a nanophase-separation heterogel (NSH) photoiontronics featuring multiple heterointerfaces capable of light-induced bidirectional modulation of ion-gradient energy conversion. Under cis- and trans-gradient light fields, distinct photoexcited built-in heterointerfacial potentials are generated to counteract and reinforce the chemical potential gradient, respectively, thereby enabling a wide-span bidirectional modulation of ion-gradient power generation. The NSH photoiontronics exhibits a high output power density of 137.62 W/m² under a 500-fold ion gradient, with bidirectional light-responsive regulation ranging from 107.91 to 198.82 W/m². Moreover, the synergistic effect of the heteronetwork enhances mechanical robustness and long-term swelling resistance while maintaining exceptional low-temperature ion modulation, indicating the outstanding environmental adaptability of NSH. The system also exhibits its large-scale performance, achieving output power densities ranging from 0.81 W/m² to 1.27 W/m² at the cm² scale. We further achieve the integration of a light-adaptive solar-osmotic energy conversion system, indicating the high compatibility of NSH photoiontronics for renewable energy utilization. The NSH photoiontronics provides a highly versatile and promising platform for field-modulated ion transport, demonstrating potential for developing intelligent ion-gradient energy conversion systems.