Metal-organic framework-derived cobalt hydroxide microparticles as supercapacitor electrode materials

In this work, cobalt hexacyanoferrate was synthesized by co-precipitation method. Then, cobalt hexacyanoferrate converted to cobalt hydroxide with a simple method, using a 0.2 M NaOH solution. The obtained composition was detected and analyzed by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive x-ray spectroscopy. The results of the identification tests confirmed the successful synthesis of cobalt hexacyanoferrate microparticles as well as cobalt hydroxide microparticles. Electrochemical measurements showed the specific capacitance of 55 F g(-1) for cobalt hexacyanoferrate in the current density of 5 A g(-1). The specific capacitance of 510.71 F g(-1) at the current density of 6 A g(-1) was obtained for cobalt hydroxide. The electrode made of cobalt hexacyanoferrate lost 45% of its initial capacitance after 1,000 continuous galvanostatic charge/discharge cycles at the current density of 1 A g(-1), whereas cobalt hydroxide was able to reach capacitance of 112.60% of own initial capacitance after 5000 continuous galvanostatic charge/discharge at the current density of 6 A g(-1).

Automated summary

Cobalt hexacyanoferrate was successfully synthesized and converted to cobalt hydroxide, with analysis conducted to confirm the synthesis. The specific capacitance and stability of the two materials were compared at different current densities, showing promising results for cobalt hydroxide in terms of capacitance retention.