Unsurprisingly, the results also show that (LiNH2+2LiH)@(6-nm PC) is far from an optimal hydrogen storage material. Its high ΔH and low k incur significant VSC penalties. As seen in Table , a large number of heat exchange tubes are required to deliver heat to the metal hydride bed for the hydrogen desorption reaction. Not only does this incur space and weight penalties, but ~34% of the total onboard hydrogen stored must be combusted to provide this heat (i.e., 5.6 kg is usable for the fuel cell, but an additional 2.9 kg is combusted). As a result, although (LiNH2+2LiH)@(6-nm PC) VSC approaches 82% of 350 bar compressed gas in an A286 tank, it remains far from the volumetric VSC of 700 bar compressed gas. Moreover, despite the significant destabilizing effect achieved by nanoscaling, the maximum operating temperature required by the storage system (387 °C) is still quite high compared to other complex hydrides. For example, sodium alanate displays a lower dehydriding ΔH and requires a maximum operating temperature of ~250 ºC. Finally, we note that this investigation focused only on the desorption of hydrogen from the metal hydride material and did not consider the problem of refueling (rehydrogenating) the material. Meeting the DOE technical target of 5 minutes for refueling is very challenging owing to the tremendous demands placed on the bed thermal management system to remove the heat of hydrogenation. Refueling will in a separate way engage all of the material properties discussed above for dehydrogenation. A useful future extension of this work, therefore, would be to investigate how the intertwined storage system features and material properties must be optimized to enable such a bed to be refueled within the five minutes required for LDVs.