N-doped porous carbon network anchoring on hollow wooden carbon fibers for high-performance electrode materials in supercapacitors

Constructing electrode materials with great ion transfer ability, highly porous, and good electrical conductivity is of significance for realizing high-performance electrochemical double-layer capacitors. Here, the N-PC (N- doped porous carbon)/ HWCF (hollow wooden carbon fiber) composites that have all the features were synthesized, which was obtained from carbonization of the mixture of hollow wood fiber (HWF)/ZIF-8 and pore-forming substances. It was found that ZIF-8 nanoparticles are closely packed forming a uniform ZIF layer fully covering the external surface of WF by the electrostatic interaction. They were converted into the inter-connect N-PC network anchoring on the HWF surface after calcination, which provided a continuous conductive network for electrons. The resulting N-PC/HWCF-based electrodes exhibited impressive electrochemical performance. The specific capacitance of N-PC/HWCF-800 is 121 F/g at a current density of 0.5 A/g with excellent cycling stability over 10000 cycles. Furthermore, the symmetrical supercapacitors (SSCs) with two N-PC/HWCF-800 electrodes delivered an encouraging energy density of 4.8 Wh kg(-1) when the power density is as high as 3600 W/kg. This study provides insights for the design of hierarchical porous carbon structure towards next-generation high-power smart devices.