Molecular clustering unlocks high-performance hydrovoltaics across temperatures from -35 °C to 80 °C.

Hydrovoltaic technologies face challenges of low conversion efficiency and narrow operational temperature ranges, limiting their practical applications in extreme environments. Here, we propose a molecular clustering strategy that leverages organic molecules to interact with organic salt anions, forming stable composite clusters. These clusters enhance water's phase change energy barrier and thermal stability while mitigating electrostatic shielding effects, effectively overcoming ion transport bottlenecks across a wide temperature range. The hydrogel achieves an operational temperature range from -35 °C to 80 °C and increases power density by an order of magnitude compared to existing technologies. Furthermore, the hydrogel demonstrates exceptional thermal and mechanical stability, maintaining stretchability above 1000% and stable performance under harsh conditions such as freezing and high heat. These advancements enable hydrovoltaic systems to operate reliably in flexible electronics, environmental monitoring, and self-powered devices across extreme environments, providing sustainable energy solutions for diverse and demanding scenarios.