In recent years, hydrovoltaic electricity generators (HEGs) have garnered increasing interest and attention due to their unparalleled advantages. They typically operate through direct interactions between various nanomaterials/structures and different forms of water (e.g., moisture, liquid water, waves, and droplets) capable of transforming diverse energy forms into electricity, resulting in the development of four types of HEGs: moisture electricity generators (MEGs), evaporation electricity generators (EEGs), droplet electricity generators (DEGs), and reverse electrodialysis electricity generators (REGs). Consequently, a deep understanding of their interactions is crucial for the development of different types of high-performance HEGs. In this regard, the efficient utilization of water by natural organisms to achieve various complex life processes and functions provides inexhaustible and ingenious inspirations for fabricating superior HEGs, establishing this as a vibrant area of current research. In this review, we will comprehensively review the recent key advancements in the field of bioinspired HEGs. We begin by elucidating the concepts and relationships between HEGs and bioinspired design, followed by an explanation of the mechanisms behind the above four types of HEGs. Building on this foundation, we systematically summarize and discuss the current progress of HEG devices from three bioinspired perspectives: (1) elementary bioinspired materials for HEGs; (2) smart bioinspired structures for HEGs; and (3) living bioinspired devices for HEGs. In this review, we will also highlight various biological structures, functions, and processes that can inspire the design of HEGs. We conclude by summarizing the challenges in the bioinspired HEG field and providing insights into future prospects for this exciting research area.

Moisture-driven electricity generators (MEGs) have been extensively researched; however, high-performance flexible variants have seldom been demonstrated. Here we present a novel complex coacervation with built-in potential strategy for developing a high-performance uniaxial MEG, featuring a core of poly(3,4-ethylenedioxythiophene) (PEDOT) with a built-in charge potential and a gel shell composed of poly(diallyldimethylammonium chloride) (PDDA) and sodium alginate (NaAlg) coacervate. The complex coacervation of two oppositely charged polyelectrolytes produces extra mobile carriers and free volume in the device; meanwhile, the PEDOT core’s surface charge significantly accelerates carrier diffusion. Consequently, the uniaxial fiber-based MEG demonstrates breakthrough performance, achieving an output voltage of up to 0.8 V, a maximum current density of 1.05 mA/cm², and a power density of 184 μW/cm² at 20% relative humidity. Moreover, the mechanical robustness is ensured for the PEDOT nanoribbon substrate without performance degradation even after 100,000 folding cycles, making it suitable for self-powered human interactive sensor and synapse. Notably, we have constructed the inaugural MEG-synapse self-powered device, with a fiber-based MEG successfully operating a synaptic memristor, thereby emulating autonomous human synapses linked with fibrous neurons. Overall, this work pioneers innovative design strategies and application scenarios for high-performance MEGs.

Heteroatom self-doped porous carbon materials were synthesized for the first time via freeze drying technique, followed by carbonization of brussel sprouts under a nitrogen atmosphere. The resultant materials were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) measurements. Brussel sprouts carbonized at 800 °C exhibit superior capacitive performance, including specific capacitance of 255 F g⁻¹ at a current density of 0.5 A g⁻¹, high rate capability (83% capacitance retention from 0.5 A g⁻¹ to 50 A g⁻¹), and good cycle life (99.5% maintained over 5000 cycles). The highly stable electrochemical performance could be due to the hierarchical porous structure combined with the high specific surface area and heteroatom doping efforts.

A novel self-assembled long Co ₃ O ₄ hollow tube network with multiple heteroatom (C-, N- and S-) doping was prepared for the first time by the combination of hydrothermal and calcination techniques using the eggshell membrane as the template and dopant.