A rubber-based sensor with over 100 million-level ultra-sensitivity (0–10% strain range) via 3D super-interface

Constrained by materials, structures, and interface, achieving high sensitivity, wide strain range, and linearity simultaneously remains an impossible triangle for flexible sensors. Herein, we propose 3D super-interface strategy based on patterned rubber substrate-conductive crack layer, successfully developing a microcrack super-interface flexible sensor (MSFS) with ultra-sensitivity (0–10% strain, GF 1.1 × 10⁸ and linearity 0.98). The 3D super-interface relies on the synergistic micro/nano level physical anchoring, and hydrogen bonding interfacial interactions between the rubber matrix and conductive crack layer, achieving strong interlayer bonding. During the sensing process, the crack structure endows the sensor ultra-sensitivity within 0–10% strain range; while the 3D super-interface ensures continuous electrical conductivity under >50% strain conditions. MSFS holds potential application value in monitoring expansion in silicon anode batteries. When the battery expansion reaches 2%, its resistance change can be as high as 22-fold. This approach enables the customized design of flexible sensors for ultra-sensitivity applications.