Scientists from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden made the sludgy gray paste, which heats hydrogen with magnesium and stabilizers so the hydrogen can be stored in cartridges even at room temperature. That's it in the photo above. What results is a stable medium that its makers say is 10 times more energy-dense than lithium-ion batteries, “When it comes time to release the energy, a plunger mechanism extrudes the paste into a chamber where it reacts with water to release hydrogen at a dynamically controlled rate, which then feeds a fuel cell to create electrical power with which to run an EV powertrain or other device. Part of the paste's impressive energy density comes from the fact that half of the hydrogen released comes from the water it reacts with.”