Hierarchically porous carbon derived from magnesium-based metal-organic frameworks as advanced active material for supercapacitor

• The derived carbon has a spherical shape and large surface area with abundant pore structure. • The carbon displays a high specific capacitance of 362.5 F g −1 at 1 A g −1 with superb rate performance. • It has superb durability with only 5.8% decline rate of original capacitance after 1.5×10 5 cycles. • The assembled supercapacitor offers energy density of 15.6 Wh kg −1 in alkaline solution. Metal-organic frameworks (MOFs) have been received great interest to prepare porous carbon with unique morphology and abounding channels for fast migration of electrolyte ions and electrons in the energy storage field. Herein, a simple preparation approach is developed to derive hierarchically activated porous carbon from magnesium (Mg)-based MOF as precursor through carbonization followed by KOH activation processes. The attained activated carbon material displays a well-organized spherical structure with 2–5 µm diameter and high specific surface area (SSA) of 2175 m² g −1 . In the three-electrode test system, the carbon electrode offers a high specific capacitance of 362.5 F g −1 at 1 A g −1 and still preserves 63.6% capacitance when the applied current density expands 100 times, revealing the excellent capacitive and rate ability. Meanwhile, the porous carbon material exhibits excellent cyclic durability with 94.2% capacitance retention over 150000 cycles at 50 A g −1 . Furthermore, the assembled symmetrical supercapacitor supplies 15.6 Wh kg −1 energy density in an alkaline aqueous electrolyte. Accordingly, the present study illustrates that the as-fabricated activated porous carbon derived from Mg-MOF is a highly potential electrode material for boosting-performance supercapacitor.