Ochai-Ejeh, F.Madito, M.J.Makgopa, K.Rantho, M.N.Olaniyan, O.Manyala, N.2025-01-132025-01-132018-09-040013-4686https://doi.org/10.1016/j.electacta.2018.09.032https://hdl.handle.net/20.500.14519/1127Birnessite-type MnO2 synthesized on the surface of carbon nanotubes (CNTs) via facile hydrothermal reflux technique to produce MnO2-CNT nanocomposite and 3D microporous nanostructured activated carbon (AC) derived from cork (Quercus Suber) with good microstructural, morphological and electrochemical properties are herein reported. A hybrid supercapacitor device comprising of MnO2-CNT nanocomposite as positive electrode and AC as the negative electrode was successfully fabricated and tested for energy storage application. The device displayed a maximum working potential of up to 2 V due to the excellent synergistic contribution from the MnO2-CNT nanocomposite and AC material derived from cork (Quercus Suber). The fabricated device displayed good electrochemical performance having an energy density of ~25Wh Kg1 that corresponds to a power density of 500WKg1 at a current density of 0.5 A g1 in a 1M Li2SO4 aqueous neutral electrolyte. The device exhibited an excellent stability of ~100% coulombic efficiency after 10,000 charge-discharge cycles and excellent capacitance retention after potentiostatic floating test for 60 h.363-375 PagesenAttribution-NonCommercial-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/Birnessite-type MnO2Activated carbonHybrid deviceReflux synthesisNanocompositeArticle