A low-cost and large-area modular nickel electrode on aramid fabric for efficient solar-driven water electrolysis

We demonstrate a water splitting electrode on aramid fabric. SnS₂ is firstly synthesized on the fabric on the scale from 1 cm² to 18 cm², and nickel is subsequently electrodeposited uniformly on the SnS₂. The electrode surface is composed of nanostructured nickel oxides, which are highly efficient water splitting electrocatalysts. The Ni/SnS₂/aramid electrode can be used as a cathode for hydrogen evolution and an anode for oxygen evolution with 100% Faraday efficiency. Numerical simulation suggests intrinsic limiting factors associated with electrode upscaling in a parallel-electrode configuration. The simulation and comparison with our experimental data suggest that OH⁻ depletion at the surface and the porosity of the electrodes introduce a significant voltage loss with increasing electrode area in a parallel-electrode configuration, which cannot be solved by nanostructuring. The efficient water splitting is attributed to the highly nanostructured surface, providing a significantly large quantity of surface area. The 10 cm² Ni/SnS₂/aramid electrodes exhibit 13.5% solar-to-hydrogen efficiency and 120 hours stability combined with a silicon solar cell. Our strategy using fabric materials as the electrolysis substrates not only suggests the use of inexpensive fabric materials for hydrogen production but also demonstrates the potential of a new design using flexible electrodes at low cost to achieve high efficiency of water splitting. © 2024 The Royal Society of Chemistry.