Co3O4 anchored on meshy biomass carbon derived from kelp for high-performance ultracapacitor electrode

In this paper kelp was used as the carbon precursor to prepare a biomass carbon with meshy microstructure, and Co3O4 nanoparticles were further modified on the meshy biomass carbon (MBC) by using solvothermal and pyrolysis methods. The prepared Co3O4@MBC composite combined the special structure of MBC with uniformly distributed Co3O4 nanoparticles, which provided large specific surface and good conductivity. Different methods including scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and nitrogen adsorption-desorption were used to characterize the structure and performances of composite. Co3O4@MBC composite was used to construct an electrode for supercapacitor, which had better electrochemical performance than that of pristine Co3O4 nanoparticles and MBC electrodes. The highest specific capacitance (1212.4 F g-1 at 0.5 A g-1) could be obtained with excellent cycle stability and the capacity retention was 99.5% at 2 A g-1 after 2000 cycles, which could be attributed to synergistic effects of both pseudocapacitance and electric double layer capacitance under optimized carboncobalt ratio. Furthermore, an asymmetric supercapacitor system was constructed utilizing Co3O4@MBC as positive electrode with MBC as negative electrode. This two-electrode system provided a good performance with energy density of 59.82 Wh?kg- 1 at a power density of 700 W kg-1, highlighting the potential application in efficient energy storage device.

Automated summary

A meshy biomass carbon was prepared using kelp as the carbon precursor, and Co3O4 nanoparticles were modified on it to form a Co3O4@MBC composite. This composite exhibited excellent electrochemical performance with high specific capacitance and cycle stability. It can be used as an electrode for supercapacitors and has potential applications in efficient energy storage devices.