This medium releases 99.99 percent pure hydrogen, which could power electrical grids, hydrogen fuel cells, cars, or hydrogen-injected diesel trucks. Former computer-chip manufacturing engineer Paul Smith founded Plasma Kinetics in 2008. The Arizona-based startup has developed “solid-state” hydrogen storage, essentially transferring the gas onto a proprietary film wound in many layers inside a canister. He says the tech could challenge batteries in both efficiency and environmental friendliness. When unspooled and run past a laser—the film moves from one reel to another, like movie film through a projector—the solid-state storage medium releases 99.99 percent pure hydrogen, which could power electrical grids,...