Emerging bioinspired hydrovoltaic electricity generators

Abstract

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.