Here is a thread on cells similar to the Hixon:
I don’t think any of the current LiIon/NiMh chargers can charge this type of cell. The dedicated charger would be required.
Read the Xtar thread, there are some upsides to this kind of cell. But they are not ideal for some applications.
They do have a LiIon cell inside that is the typical 3.6V nominal but charges to 4.2 as is typical. They then use a (lossy) buck converter to get the 1.5 V out.
There are also a few reviews of this 1.5V LiIon with buck converter type cells on BLF as well as other places if you do a search. A couple of these are linked in the thread above.
They are fairly recent, but have been around for… maybe a couple of years.