Keeping in contact with lithium

Solid-state lithium batteries are considered an attractive option for powering electric vehicles because of substantial improvements in their energy storage capacity and improved safety. However, the interface between the lithium metal anode and the solid electrolyte is structurally unstable, which causes deterioration at the point of contact at the interface and ultimately battery failure, even at moderate rates of discharge. Preventing this contact loss during operation often requires applying an impractically high compressive force to the battery cell (a high stack pressure). On page 1062 of this issue, Yoon et al. (1) report that adding electrochemically inactive sodium to the lithium metal anode improves the interfacial contact, even under a low stack pressure. This could unlock a large-scale solidstate battery capable of the fast discharge rates required for the acceleration of electric vehicles.