Wood-based carbon tubes with low-tortuosity and open tubular structure for energy storage application

The diffusion and storage of ions and transport of electrons are main factors affecting the performance of supercapacitors. The unique elongated carbon tubes with low-tortuosity and open tubular structure can improve ion diffusion and charge conduction simultaneously. In this paper, the elongated carbon tubes with low-tortuosity and open tubular structure were prepared from the delignified slender wood tubes by using simple chemical delignification and carbonization methods. The wood-based carbon tube has a gravimetric specific capacitance of 139 F g−1 at a current density of 0.25 A g−1. The wood-based carbon tube foam film exhibits a typical stacked structure with abundant stacked voids and 3D network structure, which imparts its excellent flexibility and conductivity. The stacked 3D network structure endows the good permeability of the PVA gel electrolyte. The areal specific capacitance of the WCT-800 wood-based carbon tube interdigital flexible solid supercapacitor is 74 mF cm−2 at a current density of 100 μA cm−2, which still remains at 58 mF cm−2 at 1000 μA cm−2. The interdigital flexible solid supercapacitor also exhibits good flexibility and folding endurance: about 116% of capacitance retention after 10000 folding cycles.Graphical abstractWood-derived slender carbon tubes with low-tortuosity and open tubular structure shows great potential application in the field of energy storage.