Porous Layered Carbon with Interconnected Pore Structure Derived from Reed Membranes for Supercapacitors

In this work, unique porous layer-stacking active carbon (RHC), using natural reed membranes as precursor, was prepared by a green and facile hydrothermal treatment and following carbonization process. The graphene-like RHC possesses abundant and interconnected pore structures, which can provide large active surfaces and wide ion transport paths to ensure rapid electrolyte ions storage and diffusion. In addition, abundant heteroatoms of raw materials have been retained well due to less alkali content and lower carbonization temperature, contributing to additional pseudocapacitance. As a result, the RHC electrode is endowed with desirable electrochemical behaviors. In 6 M KOH electrolyte, the as-prepared electrodes exhibit excellent specific capacitance (353.6 F g(-1) at a current density of 0.5 A g(-1)), long cycle stability (3.9% specific capacitance loss after 10 000 cycles) and good rate capability (76.9% specific capacitance retention from 0.5 to 10 A g(-1)). Meanwhile, the assembled symmetrical supercapacitor (RHCHRHC) holds a superior energy density (11.6 Wh kg(-1) at a power density of 210 W kg(-1)) and good cycling stability (99.0% specific capacitance and 80% energy efficiency retention after 5000 cycles). The exciting performance suggests that a simple and common design of porous carbon from layered biomass for supercapacitor is feasible and promising.