Large-Scale Coating Methods for Improving Heat Transfer and Stress Management of Metal Hydrides
- Posted
- Server
- Preprints.org
- DOI
- 10.20944/preprints202603.2290.v1
Storing hydrogen in interstitial metal hydrides has the advantage of high volumetric capacity (50–100 kg/m3), fast kinetics, and safer conditions due to mild temperature (< 100 °C) and pressure (< 50 bar) operation parameters. However, thermal management and stress development are still challenges that have to be overcome. There have already been promising methods to improve the performance of metal hydrides, but most of these methods are only proof-of-concepts and investigated on a lab scale with a few grams of sample. In this work, a commercially available AB2-metal alloy is coated with 10 wt% of expanded natural graphite and 10 wt% of an elastomeric binder. The focus is on methods that can easily be scaled up. Two methods (wash-coating and spray-coating) are applied successfully to prepare hydride-forming materials on a kilogram scale. The performance of the coated material regarding heat management, stress development, hydrogen capacity, and kinetics is tested for 50 cycles of hydrogen absorption/desorption. The results are confirmed by a larger-scale set of experiments with ≈0.5 kg of sample. The spray-coating method shows promising results by combining fast preparation, reasonable hydrogen capacity, and the possibility of compensating for most of the expansion stress.