alt Hacker NewsThere are different LIPO chemistries. LFP in particular has little problem with being fully charged. You'll see it get swapped in for lead acid chemistries even in places like car/motorcycle batteries.
If you want an Lithium power supply then the keyword to look for is "LFP".
And LFP is also cheaper per unit energy and less of a fire hazard. Hard to imagine why you would use a different lithium-chemistry in a UPS.