Morphogenic Interfaces for Solid-State Lithium Batteries

Solid-state lithium batteries (SSBs) offer great energy density and inherent safety; nevertheless, their commercialization is impeded by interfacial instability between lithium metal and solid electrolytes. This Commentary emphasizes a newly suggested solution: interfacial morphogenesis─a dynamic approach inspired by biological systems. This method employs a lithium–sodium (Li–Na) binary metal anode characterized by electrochemically inactive, low-yield-strength Na domains that autonomously assemble and relocate to occupy gaps created during lithium stripping. These domains undergo plastic deformation under cyclic stress, ensuring close contact with the solid electrolyte and reducing interfacial resistance and filament growth, independent of high stack pressures or hard interlayers. We examine the experimental and modeling data that illustrate enhanced stripping capacity, extended cycling stability, and strong interfacial contact. The Li–Na combination attains elevated capacities even at reduced pressures (e.g., 16 mAh cm–2 at 0.8 MPa with 5% Na), surpassing pure lithium under analogous conditions. This morphogenic interface concept signifies a paradigm leap in SSB interface design, facilitating adaptive, low-pressure, and scalable structures. Future initiatives involve improving the morphology of secondary phases and applying this method to additional soft-metal systems.