Synthesis of highly porous hybrid nanocomposite of hemp derived carbon nanosheet/carbon nanotube/manganese cobalt oxide for asymmetric supercapacitor

Abstract

This article outlines a simple and affordable strategy for creating 3D mesoporous structures from biomass. Three-dimensional hemp-derived carbon/carbon nanotube/manganese cobalt oxide hybrid electrode material was successfully fabricated. Derived from natural hemp fibre, such electrodes exhibited rich surface area with improved ion transportation kinetics. In our approach, hemp-based carbon-CNT was synthesized by varying the ratio of hemp and CNT. Finally, a ternary composite was prepared by taking the best ratio of hemp-CNT onto which manganese cobalt oxide was assembled. The synthesized ternary mesoporous material has a surface area of 380.85 m2 g−1 and exhibits outstanding cyclic stability (94%) in 1 (M) TEABF4/DMSO electrolyte, making it an excellent electrode material with a capacitance (Sp.C) of 1083 F g−1 at 1 A g−1. Further, the electrode material was assembled as a cathode in asymmetric supercapacitor and among different electrolytes. Excellent electrochemical performance was obtained in ionic liquid (NHEt3+HSO4−). The fabricated device exhibits a specific capacitance of 62.5 F g−1, energy density of 28 W h kg−1 and power density of 900 W kg. The fabricated asymmetric supercapacitor can power a 1.8 V red LED light for 3 min and 55 s after 30 s of charging. Therefore, this work shows that agricultural biomass can be a viable supercapacitor electrode material.