This company called Plasma Kinetics has developed a thin film that can store hydrogen at the same volume as a 5000 PSI cylinder but lighter, and lighter than batteries. The medium can be very thin film or disks. The hydrogen is released by shining a laser onto the film. Because the hydrogen does not have to be compressed, the process uses less energy and is more efficient. Also the hydrogen is not under high pressure so less of a fire and safety hazard.
A high pressure hydrogen fueling station costs a few million dollars; the hydrogen fueling station using PK’s cartridges costs a few hundred thousand.
It’s still in development but there is room for improvement.