Flexible Garnet Solid-State Electrolyte Membranes Enabled by Tile-and-Grout Design

Inorganic solid-state electrolytes for lithium metal batteries have attracted significant interest, but their brittle nature creates a severe hurdle to widespread application in flexible electronics. Herein, we propose the rational design of a flexible electrolyte membrane with a tile-and-grout pattern in which garnet-type electrolyte tile-like chips are joined together without gaps by styrene–butadiene copolymer using additive manufacturing. The dimensions of the garnet chips are optimized through fracture mechanics analysis, which effectively suppresses the strain energy below the fracture toughness of the garnet solid-state electrolyte, eliminating random cracking. The garnet chips function as fast lithium-ion transport channels, while the styrene–butadiene copolymer grid serves as a deformable buffer to further reduce the stress transferred to the garnet chips. The tile-and-grout design electrolyte membrane presents good flexibility and can be readily bent without breaking. Our facile and pragmatic strategy presents a new design principle for solid-state electrolytes to address the brittleness issues.