it might be possible to take syn gas, which is largely hydrogen, and [com]press filtered raw syngass into magnesium hydride pellet tanks with a max psi rating of like 75 and a regular operating psi of about 55max. remnants not adsorbed to the pellets(i dont think its called absorbson for this) could be purged out. so thereforethe system would need at least two tanks which are filled alternatively while the other purges co2 mainly with probably a back pressure of of (a guess) 26psi so as to not release to much hydrogen. once the tank starts running (in run mode, not fill mode anymore) the final co2 would be purged out with the first release from the tank. magnesium hydride pellets is a storage solution forthe future but if it was coupled with syngas production using a heat (steam) powered compressor pump it could be a great way to fill a car by throwing logs in a gasifier, stepping on a stationary bicycle to fan the fire up and assist the compressor. the speed of the syngas production would be bottleneck in speed of 'filling the tank'. unlike battery techs that take a lot of time these sort of tanks are not flamable or explosive even full of pure h2