High energy density asymmetric supercapacitors based on MOF-derived nanoporous carbon/manganese dioxide hybrids

Abstract

Nanoporous carbon materials with high specific surface areas have attracted increasing attention for electrochemical energy storage applications. Metal organic frameworks (MOF) as a good precursor for nanoporous carbon could be used as a promising substrate to improve the energy density of the electrode because of its high specific surface area and high porosity. Here we fabricated MOF-derived nanoporous carbon (MOF-NPC) by direct calcination of zine-based MOF with different carbonization temperatures and synthesized MOF-NPC/MnO2 hybrids via a self-controlled redox process with MnO2 nanostructures well confining in the porous structures of MOF-NPC. An asymmetric supercapacitor has been developed using MOF-NPC/MnO2 hybrids as positive electrode and MOF-NPC as negative electrode in a neutral aqueous Na2SO4 electrolyte. Due to the excellent structure of MOF-NPC as a porous scaffold, optimized asymmetric device could be reversibly cycled in the voltage range of 0–2.2V, and exhibits a maximum energy density of 76.02Whkg−1 (for a power density of 2.20kWkg−1) and a maximum power density of 22.00kWkg−1 (for an energy density of 49.56Whkg−1), demonstrating its strong potential for the practical applications of energy storage devices.