Liquid-like hydrogen densities in engineered carbon nanospaces

High surface area materials, such as those engineered from synthetic carbon compounds, have narrow pore sizes resulting in exceptionally high stored densities for hydrogen. Stored density is a measurement of the average hydrogen density within a pore. At supercritical temperatures and high pressures, these materials can achieve stored densities 20{\%} higher than liquid hydrogen at 1 bar and 20 K. At 77 K and 200 bar, we have achieved stored densities of up to 85 g/L. We can show, depending on the pore structure, a maximum of gravimetric hydrogen excess adsorption at 100 bar and 296 K and binding energies of 8-10 kJ/mol. The occurrence of a maximum of gravimetric excess adsorption at relatively low pressures, indicating a high binding energy, is due to the overlapping adsorption potentials in narrow pores.