The batteries are not really for long term storage - they are mostly for regulation of supply, most people don't seem to understand that. Hydrogen as a storage medium has a low roundtrip efficiency with the overall energy efficiency of a typical lithium ion battery system being ~85% compared to 30% for a regenerative hydrogen fuel cell. LiBs are getting more efficient as they are developed.
Also most people starting from 2028 or so will have a LiB parked in the garage
That said, the hydrogen separation via membrane the CSIRO are working on is an interesting avenue but seems a ways off. In any case Renewables + Nuclear as the actual power sources covers the bases without too much need for serious storage.
