Harvesting Hydropower via a Magnetoelastic Generator for Sustainable Water Splitting
Il Woo Ock, Xun Zhao, Trinny Tat, Jing Xu, Jun Chen
Abstract
Energy consumption and the resulting climate change are the two major challenges to human sustainability. Hydrogen (H2) is a form of environmentally friendly renewable energy with an extremely high energy density of 143 MJ kg–1. Water splitting is a practical and cost-effective approach to generate H2 through the decomposition of H2O by electrolysis with an external power supply. Herein, we introduce a compelling platform technology for self-powered water splitting by using a soft magnetoelastic generator to convert hydropower into electricity as a sustainable power supply for electrolysis. At a rotating speed of 469 rpm, the hydropower harvester is able to convert flowing kinetic energy into electricity and produce a high current density of 2.99 mA cm–2 at a low resistance of 60 Ω. The magnetoelastic generator is intrinsically waterproof since the magnetic field can penetrate the water molecules. As a demonstration, the device maintained a stable electrical output even in underwater situations after over 7,000 cyclic operations. The generated electricity from hydropower could produce H2 at a rate of 1.93 × 10–3 mL min–1. In conclusion, this work provides a compelling method for self-powered water splitting by using flowing kinetic energy.