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

- Nanoporous carbon materials (NPC) are fabricated by pyrolysis of MOF.
- MOF-NPC/MnO2 hybrids are synthesized via a self-controlled redox process.
- MnO2 nanostructures are well confined in the porous structures of MOF-NPC.
- Assembled asymmetric cell shows a maximum energy density of 76.02 Wh kg−1.

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 0-2.2 V, and exhibits a maximum energy density of 76.02 Wh kg−1 (for a power density of 2.20 kW kg−1) and a maximum power density of 22.00 kW kg−1 (for an energy density of 49.56 Wh kg−1), demonstrating its strong potential for the practical applications of energy storage devices.

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