Nitrogen-doped mesoporous carbon spheres decorated with NiCo alloy nanoparticles for high-performance electrochemical supercapacitors

초록

Nitrogen-doped mesoporous carbon spheres (NMCSs) decorated with NiCo alloy nanoparticles (NiCo/NMCS) were prepared and examined for their prospective role as high -performance electrode materials. The average size and BET surface of the NMCSs are 488.1 nm and 660.9 m 2 g -1 . The N content of the NMCSs and NiCo/NMCS-50 (NMCSs with 50 wt% of NiCo alloy nanoparticles (NPs)) was 1.49 wt% and 2.9 wt%, respectively. The NiCo alloy NPs, with an average diameter of 9.6 nm, were evenly incorporated into NMCSs. The NiCo/NMCS-50 exhibited a specific capacitance of 585 F g -1 when tested in a 6 M KOH solution at a current density of 1 A/g. The superior electrochemical performance of NiCo/NMCS-50 is attributed to the synergistic effect of mesoporous carbon structure and NiCo alloy NPs by improving redox-related mass transport and electron transfer. Symmetric supercapacitor devices assembled using two NiCo/NMCS-50 electrodes had a maximum energy density of 30.0 Wh kg -1 at a power density of 187.5 W kg -1 with notable cycling stability, maintaining 60.1 % of capacitance, up to 5,000 cycles. These results suggest that NiCo/NMCS composites have significant potential for utilization in high-energy storage applications.

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