Carbon Aerogels for Hydrogen Storage

摘要: This effort is focused on the design of new nanostructured carbon-based materials that meet DOE 2010 targets for on-board vehicle hydrogen storage. Carbon aerogels (CAs) are a unique class porous possess number desirable structural features storage hydrogen, including high surface areas (over 3000 m{sup 2}/g), continuous and tunable porosities, variable densities. In addition, flexibility associated with CA synthesis allows incorporation modifiers or catalysts into carbon matrix in order to alter sorption enthalpies these materials. Since properties doped CAs can be systematically modified (i.e. amount/type dopant, area, porosity), novel fabricated exhibit enhanced properties. We using this approach H{sub 2} sorbent appreciable amounts at room temperature through process known as spillover. The spillover involves dissociative chemisorption molecular supported metal catalyst (e.g. platinum nickel), followed by diffusion atomic onto support material. Due interaction between support, stored inmore » material more reasonable operating temperatures. While has been shown increase reversible capacities metal-loaded nanostructures, issues still exist approach, slow kinetics uptake ({approx} 1.2 wt% carbon) below targets. ability tailor different aspects system size/shape particle, catalyst-support interface morphology) should provide valuable mechanistic information regarding critical dissociation, recombination) allow optimization parallel effort, we also designing nanoporous scaffolds hydride systems. Recent work others demonstrated hydrides show relative bulk effect diminished, however, after several hydriding/dehydriding cycles, structure coarsens. Incorporation scaffolding potentially limit coarsening and, therefore, preserve improved cycling behavior hydride. Success implementation requires solids large accessible pore volumes (> 4 cm{sup 3}/g) minimize gravimetric volumetric capacity penalties use scaffold. scaffold capable managing thermal changes incorporated promising candidates such due porosity aerogel framework. research joint HRL Laboratories, member Metal Hydride Center Excellence. LLNL's efforts have requirements, while evaluation performance composites performed HRL.« less