(731g) Strategies Toward Enhanced Low-Pressure Volumetric Hydrogen Storage in Nanoporous Cryoadsorbents

Volumetric hydrogen capacity remains one of the most challenging criteria for on-board hydrogen storage system requirements. We present here a new concept for hydrogen storage for porous aromatic frameworks (PAFs) impregnated with lithium-decorated fullerenes (Li₆C₆₀). The loading of Li₆C₆₀ and the effect on the adsorption of hydrogen (H₂) has been investigated by molecular simulation. It is shown that the incorporation of Li₆C₆₀ can enhance the volumetric capacity of H₂ from 12 to 44 g/L, a 260% increase at 10 bar and 77 K. The impregnation of Li₆C₆₀ increases the heat of adsorption and surface area at the cost of the available pore volume. However, the increase in adsorbed hydrogen outweighs any pore volume loss under optimized Li₆C₆₀ loading and operating conditions. In addition, the H₂ volumetric uptake is shown to correlate with the volumetric surface area at all pressures, whereas the H₂ gravimetric uptake correlates with the heat of adsorption at low pressures, surface area at moderate pressures, and pore volume at high pressures.