N-doped porous carbon with ZIF-67-derived CoFe₂O₄-Fe particles for supercapacitors

The development of novel materials for electrodes with high energy densities is essential to the advancement of energy storage technologies. In this study, N-doped layered porous carbon with ZIF-67-derived binary CoFe₂O₄-Fe particles was successfully fabricated by the pyrolysis of an Fe-based chitosan (CS) hydrogel mixed with ZIF-67 particles. Various characterization techniques were employed to assess the performance of the prepared porous CoFe₂O₄-Fe@NC composite. This composite exhibits excellent performance owing to the effective combination of multivalent CoFe₂O₄-Fe particles derived from ZIF-67 with N-doped porous carbon substances with a high surface area, which helps to accelerate ion and charge transfer. The specific capacitance of the CoFe₂O₄-Fe@NC composite carbonized at 700 °C reached 3960.9F/g at 1 A/g. When this composite is combined with activated carbon (AC) to construct an asymmetric supercapacitor (ASC), a density of energy of up to 84.9 W h kg^-1 is attained at a power capacity of 291.6 W kg^-1. Moreover, this composite maintained a capacitance retention of up to 94.9 % after 10,000 cycles. This work offers new perspectives on high-performance supercapacitors and their applications.