Interface morphogenesis with a deformable secondary phase in solid-state lithium batteries

The complex morphological evolution of lithium metal at the solid-state electrolyte interface limits performance of solid-state batteries, leading to inhomogeneous reactions and contact loss. Inspired by biological morphogenesis, we developed an interfacial self-regulation concept in which a deformable secondary phase dynamically aggregates at the interface in response to local electro-chemo-mechanical stimuli, enhancing contact. The stripping of a lithium electrode that contains 5 to 20 mole % electrochemically inactive sodium domains causes spontaneous sodium accumulation across the interface, with the sodium deforming to attain intimate electrical contact without blocking lithium transport. This process,…