An excellent speaker who knows how to make a 700oC/0.5 V battery sound attractive :)

Great, been following that since the beginning... The only viable solution formulated till now, by far, where electricity is stored as electricity (instead of the dynamic potential of a mountainous lake/dam, or the kinetic potential of a gigantic flywheel, for example)... This is a humanity-dream come true, in a world so corrupt, where Lithium-batteries are still considered a suitable solution for mass-storage... Of course, using a cheap battery means, that the profit-margins are smaller, so, except Sadoway, none follows that route, since the target is always profit-maximization, and not ecology, or future energy-safety. But there´s places outside of the US, where the people are neither blinded by profit-maximization, nor blind to the climate crisis... Lithium can surely not be part of the solution, since the amount of Lithium that exists in the world, is maybe enough for a single medium-sized-country, but there´s hundreds of countries, and some of them are huge. Bismut, as mentioned, would be an even tiny-bit-better substance, but, of course, it´d be irresponsible to take Vietnam´s Bismut for that, cause that´s what Vietman has to use fot its own locally built Ambri-batteries... Aside to that, it´s too expensive for everyone else, but the Vietnamese... The cycle-efficiency can of course rise, by building well-isolated walls around the sum of all those ship-container-sized-batteries, that make up a single power-plant... There´s nowadays no reason that heat escapes, surely not with the help of some german expertise (here, there´s passive houses, that need just 30 gallons of oil for their entire annual heating-needs, and cost just 8% more than normal houses, 2010 figures)... But the cycle-efficiency is fairly high anyway, maybe falling 10% short of the best batteries out there, that are completely unsuitable for mass-electricity-storage...

I can´t see what is he pointing at.