Facile hydrothermal synthesis of tubular kapok fiber/MnO2 composites and application in supercapacitors

Kapok fiber/MnO2 (TKF/MnO2) composites with a tubular structure are successfully fabricated via a facile hydrothermal process. Potassium permanganate and kapok fiber served as the manganese source and the template, respectively. The effects of operating parameters including material proportion, reaction temperature, reaction time and the growth mechanism of MnO2 are studied in detail. A maximum specific capacitance of 117 F g(-1) has been achieved at 0.25 A g(-1) in 1 M Na2SO4 and 95% specific capacitance is maintained after 1000 cycles, which demonstrates the potential application of tubular TKF/MnO2 composites in supercapacitors. The superior electrochemical performances of the obtained composites are attributed to their hollow structure, thin wall thickness, and orderly pore passages, which can facilitate ion diffusion and improve the utilization of the electroactive sites of MnO2.