3 ms·

There was some news about metal sponges earlier that may be able to hold high volumes of H2 under low pressure. https://www.bbc.com/news/science-environment-52

• mannykannot 6y ago
  You got me thinking, so I looked for some numbers. Hydrogen has a specific energy of 120 MJ/kg, while Kerosine has 46 MJ/kg. According to the abstract of the paper being discussed here, the new material has a deliverable capacity of 14% by weight, corresponding to about 17 MJ/kg - only a bit better than 1/3 that of kerosine, but considerably better than lithium ion batteries, which apparently achieve less than 1 MJ/kg, while the best-performing lithium-sulfur batteries are at about 1.8 MJ/kg. In addition, we must deal with this material only losing 14% of its weight as its hydrogen is used up, while kerosine loses all of its weight - a combustion-powered airplane becomes more efficient as its fuel is consumed. Furthermore, to get that 14% deliverable capacity, you have to start with it at 100 bar, so the tank containing it will have a substantial weight. So we have progress here, but not yet a substitute for liquid hydrocarbons.