Bioinspired marine hydrogen mining via electrolysis powered by in-situ stream current energy

Abstract

Electrolyzing seawater with in-situ renewable energy is one of the most sustainable approaches for hydrogen production. Current technologies only exploit the shallow sea surface, leaving great potentials underneath, which can profoundly improve utilization of marine space and energy of water stream. To realize three-dimensional systems of sustainable marine hydrogen exploitation, challenges such as local energy harvesting, structure resilience, vertical transportation of products should be well tackled. Here, inspired by the giant kelp which can withstand severe marine conditions and deliver nutrient vertically, a novel system capable of mining hydrogen in different water depths powered by in-situ water-current energy is designed. The system consists of flexible stems anchored on seafloor and stretching toward water surface by buoyancy. Rationally designed flexible triboelectric nanogenerators (TENGs) with simple manufacturing process are attached to stems, harvesting flow energy to electrolyze seawater, and produced hydrogen bubbles are transported upward along vessels inside stems by buoyancy. Moreover, a charge excitation strategy is successfully integrated, improving the charge output by 15.3 times and realizing new performance level for water-current energy harvesting to well satisfy the high requirement of electrolysis. The paper provides a novel strategy for more efficient stream energy harvesting and mining hydrogen vertically in different depths for practical applications.