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Abstract In this work, a Co-ZIF material and the derived nanoporous cobalt-rich carbons by direct carbonization of this Co-ZIF material were synthesized and used as electrode materials for supercapacitors. This ZIF material exhibited a high specific capacitance of 160.3 F g−1 at 0.5 A g−1, an excellent rate capability (73.72 F g−1 at 10 A g−1), and a good cycling stability with 100% of its initials specific capacitance after 8000 cycles. In addition, the obtained derived nanoporous carbons displayed ideal capacitor behaviors and were promising electroactive materials for supercapacitors at low current density. The nanoporous carbon obtained at 650 °C possessed a highest specific capacitance of 393 F g−1 at 0.5 A g−1 and a wide potential application range of −1.0–0.33 V. In addition, a symmetric supercapacitor device consisting of Z-C-650 and activated carbon exhibited a maximum energy density of 61.23 Wh Kg−1 at a power density of 700 W kg−1 and predicted that Z-C-650 could be used as a potential energy storage material. Graphical abstract Image 1 Highlights • Cobalt zeolite imidazolate framework and derived nanoporous carbons were prepared. • The framework and the derived carbons showed good electrochemical properties. • The assembled symmetric supercapacitor showed good performances. • The capacitor had energy density of 61.23 Wh kg−1 at 700 W kg−1 power density. [ABSTRACT FROM AUTHOR]

The demand for energy storage equipment in the information age era is becoming increasingly scarce, but manganese-based metal oxides with large potential windows and multivalent states were developed and used as high-performance electrode materials for energy storage. MnO 2 array grow on the carbon sphere as the precursor and then obtain multi-types and hierarchical of manganese metal oxides through gradient carbonization. The surface crystal phase changes with temperature, and the electrochemical performance shows obvious imparity. In addition, the carbon spheres gradually disappear with increasing temperature forming a hollow shell structure, which is conducive to sufficient contact between electrolyte and electrode material. It found that the annealing temperature can change the surface oxide morphology of MnO 2 /C, and it can know that the temperature promotes the conversion of MnO 2 to Mn 2 O 3 and Mn 3 O 4. Based on the oxides of different crystal phases, the electrochemical properties are more distinctive due to their different structures. The rod-like nanoarray Mn 2 O 3 /C composites derived from annealing the precursors at 600 °C show high specific capacity and rate performance under a very large potential window of 0~1.2 V (show a remarkable specific capacitance of 277.0 F·g−1 at a current density of 1.0 A·g−1). Considering practical application, the as-assembles Mn 2 O 3 /C//Na 2 SO 4 //Mn 2 O 3 /C symmetrical supercapacitors device exhibits a maximum energy density of 80.35 Wh·kg−1 at a power density of 500 W·kg−1, which can be applied promising storage materials for information age. [Display omitted] • Oxide nanowires grow uniformly on the surface of carbon spheres in situ. • The annealing temperature greatly affects the phase transition and structure. • Carbon-enriched Mn x O y and derived nanosphere have excellent electrochemical performance. • It is found that the electrochemical performance is greatly affected by the morphology and structure. • The Mn 2 O 3 /C//Na 2 SO 4 //Mn 2 O 3 /C exhibits a high energy density of 80.35 Wh·kg-1 at a power density of 500 W·kg-1. [ABSTRACT FROM AUTHOR]