Asymmetric supercapacitor based on novel coal fly ash derived metal–organic frameworks as positive electrode and its derived carbon as negative electrode

The paper presents a comparative study between aluminum fumarate metal–organic framework (Al-FumMOF) and a novel coal fly ash derived aluminum MOF (CFA-FumMOF) with their respective MOF-derived carbons (MDCs) for electrochemical performance in supercapacitor application. In the half-cell configuration, Al-FumMOF possessed the highest specific capacity value of 28.62 mAh g⁻¹ and CFA-FumMOF with 9.88 mAh g⁻¹ at a specific current of 0.5 A g⁻¹ in 6 M KOH electrolyte. The carbon derivative from CFA-FumMOF possessed the highest specific capacitance of 306.59 F g⁻¹ at 0.5 A g⁻¹ as compared to carbon obtained from Al-FumMOF (111.94 F g⁻¹). Each MOF was prepared with its respective carbon derivative for an asymmetrical capacitor device with a specific capacity of 5.09 mAh g⁻¹ at 0.5 A g⁻¹. Graphical abstract: [Figure not available: see fulltext.]