[Heston]

"...the problem they face going through cycles of discharging and recharging in a stable way."

They suffer from poor wearing like almost all new battery technologies. Until that's solved they aren't useful.

[lonk11]

The article is about a solution to make lithium metal anode more stable. They discovered a coating that prevents the formation of dendrites, which are the cause of short cycle life of previous attempts at lithium metal anodes.