Comment Re:I hope they succeed (Score 1) 64
Lithium-ion batteries are inherently rather tricky to build. And lithium itself isn't all that widely available, though it's not exactly rare. Zinc, though, is so cheap they make pennies out of it. Lithium has higher density, but for stationary use, who cares? The competition might be sulfur-based batteries. But those run at very high temperatures, and don't scale down well.