That is shockingly good. EIA reports existing grid scale battery round trip is like 82% which do not have moving parts.

  ...in 2019, the U.S. utility-scale battery fleet operated with an average monthly round-trip efficiency of 82%, and pumped-storage facilities operated with an average monthly round-trip efficiency of 79%.... 

> existing grid scale battery round trip is like 82% which do not have moving parts.

This is incorrect for a lot of containerized lithium systems. They have a lot of moving parts in their AC systems - the compressors, the fans, the cooling water pumps.

Lithium cells really don't like to be hot. If you put them next to solar farms in the sun belt or if you discharge them moderately quickly, you'll have to cool them. This cooling system also eats into the overall efficiency, but what's even worse is that its the majority of the maintenance budget.