Astronaut Power Cells
So we can make items to refill the oxygen and hydrogen of a suit, but not its energy. And yet, in space at least, energy is consistently what runs out first by a large margin. I don't even bother carrying oxygen or hydrogen bottles with me when I'm exploring nearby asteroids anymore because I know I'll have to return for more energy long before I use them.
There really needs to be a craftable energy item (e.g. a battery or power cell) that can recharge an astronaut suit.
That would be the primary use case, but as a bonus it could also be designed so that it can recharge a battery by, say, clicking on the battery (or some interface that doesn't require a the conveyor). Or maybe even create a recharge port block that accepts it. That would be extremely useful to jumpstart grids that have run out of power. For this usage, it just needs to be enough power to get some other power system operating properly (e.g. powering an O2/H2 generator and a conveyor system just long enough to put some ice in so that it can then power a hydrogen engine or powering a conveyor system just long enough to place uranium in a reactor).