>They can attain the same level of efficiency as a li-ion battery and not any more complex.
No, they cannot attain the same level of efficiency. It's not even close, and no one who was arguing in good faith and had done even the most cursory research on the issue would make that absurd claim.
https://tide.theimi.org.uk/industry-latest/motorpro/efficien....
https://www.linkedin.com/pulse/mirai-fcev-vs-model-3-bev-pau...
You're just making stuff up. We're done here.