Solar-driven water splitting at 13.8% solar-to-hydrogen efficiency
Lithium iron phosphate batteries have about 95% round trip efficiency. Some manufacturers say 98%. AC-DC-AC conversion is around 98%-99% efficiency now. So batteries are way ahead on efficiency.Tesla is switching from lithium-ion to lithium iron phosphate for fixed battery installations.[1] The energy per unit weight is somewhat lower, but that doesn't matter much for fixed installations. The safety is better, too - lithium iron phosphate batteries don't have the thermal runaway problem.  BYD, which is the biggest producer of batteries in the world, sells shipping container sized lithium iron phosphate sized battery packs for large scale solar backup.[1] https://www.utilitydive.com/news/tesla-shifts-battery-chemis...