The zinc batteries have a volumetric energy density of 100 Wh/L, compared to, say, 450 Wh/L for the NMC lithium battery in a Tesla. you need 4.5x as much physical space to hold the same amount of energy.

That may not be a dealbreaker for many applications. Replace a Powerwall with a dorm-fridge sized one of these in your basement or garage and you’d probably be just as happy (and happier still if it’s cheap).