Lithium battery UPS? Concerns?

Going to have to look around a bit more. I’ve been buying APC 2200va with an extra battery to double the run time (no generator). XPCC doesn’t have any Lithium that offer an extra battery for longer run time and I don’t really need to step into a 10,000va device. Power goes out often enough that I need to make sure I have about an hour per UPS with the load I put on them.