Bamboo-inspired cell-scale assembly for energy device applications

Rapid advances in flexible and wearable smart textiles demand low-cost, high-energy/power-density fiber-shaped supercapacitors (FSCs). The performance of FSCs is determined by the fabrication and assembly of fiber-shaped electrodes (FSEs), where an active charge-storage material is always clad around flexible charge transmission current collectors. Inspired by the tissue structure of natural bamboo, wherein parenchyma cells (PCs) that store nutrients are clad around bamboo fibers (BFs), we propose a strategy for converting bamboo cells into FSEs using conductive BFs and activated PCs as current collectors and active materials, respectively. The assembled electrode has a high specific capacitance of 1454 mF cm −2 at 0.64 mA cm −2 . A solid-state FSC with a pair of bamboo-structured electrodes exhibited a substantially high energy density. Its mechanical flexibility enabled the knitting of wearable wristbands to drive ultra-small voltmeter indicators. This lightweight, low cost, and high-energy-density bamboo-structured FSC could enable numerous smart textile applications.