Creep-Enabled 3D Solid-State Lithium-Metal Battery

Summary

Existing all-solid-state Li-metal batteries suffer attacks by the chemically aggressive and mechanically stressful Li metal. Li metal is a soft crystal and may exhibit either displacive or diffusive deformation. Here, we describe a class of all-solid-state Li-metal batteries enabled by 3D porous Li-metal hosts made of electrochemically stable mixed Li-ion and electronic conductor (MIEC) and electronic and Li-ion insulators (ELI). Within 3D open porous MIEC/ELI structure, Li metal advances and retracts via interfacial diffusional creep as an "incompressible working fluid" with fast stress relaxation and minimal contact with a solid electrolyte (SE), thereby significantly improving the electrochemomechanical stability. In situ transmission electron microscopy corroborated with thermodynamic analyses offers design principles in materials, sizes, and interfaces of the 3D porous MIEC/ELI structures, which are applicable to other alkali-metal batteries. The successful construction of a creep-enabled battery engine opens a new avenue toward high-density, electrochemically and mechanically robust all-solid-state Li-metal batteries.