To be fair, these are research projects. The things they describe usually work, but may not have all the properties you would need to make a commercially successful battery. For example, the cell voltage; it should be as high as possible, some cell types are below 1 volt, which is really too low. Or it may not have very good current capacity, so you'd need excessively large membranes. Or loads of other things.
This is primary research, they're announcing that they've managed to get excellent stability, via some mechanism; even if this particular cell doesn't tick all the boxes, the same trick might be applied to other cells to give a really good battery.
And while I haven't read this paper, for a paper to be published it nearly always has to reveal what they did in sufficient detail that it could be reproduced.