A biomimetic conductive super-foldable material

The further development of flexible electronics inevitably requires conductive materials to have numerous foldable properties; however, that has not been realized. Here, inspired by silkworm cocooning processes, we prepare a super-foldable conductive carbon material with layered nanofiber network structures through an improved electrospinning/carbonization technique. It can remarkably bear 1,000,000 times repeated true-folding without structural damage and conductivity fluctuations. The root of such performance breakthrough is revealed through real-time SEM folding observation and mechanical simulations. Its structures featuring appropriate pores, non-crosslinked junctions, slidable nanofibers, separable layers, and a compressible network can act synergistically to generate a ε-like folding construction at crease under true-folding, which can completely disperse stress via bulged layers, dispersed arcs, and slidable grooves in ε. Consequently, each nanofiber avoids directly facing with 180° folding when the whole material is true-folded. This work embodies structure innovation, performance breakthrough, and mechanism reveal, which has great scientific significance and application prospects.