Scalable Production of Wearable Solid‐State Li‐Ion Capacitors from N‐Doped Hierarchical Carbon

Abstract Smart and wearable electronics have aroused substantial demand for flexible portable power sources, but it remains a large challenge to realize scalable production of wearable batteries/supercapacitors with high electrochemical performance and remarkable flexibility simultaneously. Here, a scalable approach is developed to prepare wearable solid‐state lithium‐ion capacitors (LICs) with superior performance enabled by synergetic engineering from materials to device architecture. Nitrogen‐doped hierarchical carbon (HC) composed of 1D carbon nanofibers welded with 2D carbon nanosheets is synthesized via a unique self‐propagating high‐temperature synthesis (SHS) technique, which exhibits superior electrochemical performance. Subsequently, inspired by origami, here, wave‐shaped LIC punch‐cells based on the above materials are designed by employing a compatible and scalable post‐imprint technology. Finite elemental analysis (FEA) confirms that the bending stress of the punch‐cell can be offset effectively, benefiting from the wave architecture. The wearable solid‐state LIC punch‐cell exhibits large energy density, long cyclic stability, and superior flexibility. This study demonstrates great promise for scalable fabrication of wearable energy‐storage systems.