They might be lithium tin zinc batteries, they've been successfully constructed by at least one guy in china who published a paper on it. we followed his paper and procured all the materials we needed to try and build our own, but so far we've been busy with other things and haven't time to get back into it. we did a trial run with some LiFEPO4 cells, and built ten little pouch cells. they were pretty low capacity, but it was just to test our facilities. initial results were pretty good, we were able to charge and discharge them and took some data. for LIFE batteries all of the anode and cathode plates are already available (they're just copper and aluminum with the chemicals plated on them) but for the lithium tin zinc cells we have to prepare our own anode and cathode (actually i think one is just an aluminum sheet, and the other is copper plated with the chemicals.) I wasn't super involved in the project but i know most of the details. The advantage of the batteries is that the guy in china found them to initially be about 5 times more energy dense than LiFEPO4. The downside was that they started losing capacity fairly early, maybe around a couple of hundred cycles.