Super‐Aerophilic Biomimetic Cactus for Underwater Dispersed Microbubble Capture, Self‐Transport, Coalescence, and Energy Harvesting

Abstract Human ocean activities are inseparable from the supply of energy. The energy contained in the gas‐phase components dispersed in seawater is a potential universal energy source for eupelagic or deep‐sea equipment. However, the low energy density of bubbles dispersed in water introduces severe challenges to the potential energy harvesting of gas‐phase components. Here, a super‐aerophilic biomimetic cactus is developed for underwater dispersive microbubble capture and energy harvesting. The bubbles captured by the super‐aerophilic biomimetic cactus spines, driven by the surface tension and liquid pressure, undergo automatic transport, coalescence, accumulation, and concentrated release. The formerly unavailable low‐density dispersive surface free energy of the bubbles is converted into high‐density concentrated gas buoyancy potential energy, thereby providing an energy source for underwater in situ electricity generation. Experiments show a continuous process of microbubble capture by the biomimetic cactus and demonstrate a 22.76‐times increase in output power and a 3.56‐times enhancement in electrical energy production compared with a conventional bubble energy harvesting device. The output energy density is 3.64 times that of the existing bubble energy generator. This work provides a novel approach for dispersive gas‐phase potential energy harvesting in seawater, opening up promising prospects for wide‐area in situ energy supply in underwater environments.