Extremely Versatile Deformability beyond Materiality: A New Material Platform through Simple Cutting for Rugged Batteries

A rugged lithium‐ion battery (LIB) can be realized without any new material development through selective material matching based on localized deformation of a substrate induced by its well‐designed pattern. In particular, an auxetic cut flexible substrate accommodates various complex deformations and adaptive conformations through the hinge joints because the external force is highly localized in the hinges while the segmented motifs remain almost undeformed. The embedded LIB cells in undeformed regions of the auxetic cut silicon rubber sheet do not undergo large deformation, maintaining their battery performance regardless of loading conditions via the pattern‐associated deformation mechanism. The hierarchy and number of segmentations are the key parameters of the deformation mechanism for auxetic cut shape‐reconfigurable battery systems. The numerically and experimentally proven strategy that utilizes strain gradients induced by a patterned substrate as a design guideline for material matching can lead to various wearable and conformable designs without sacrificing the functionality and durability of electronic devices.