Metal-organic-framework derived carbon polyhedron and carbon nanotube hybrids as electrode for electrochemical supercapacitor and capacitive deionization

In this work, carbon polyhedron and carbon nanotube hybrids (HCN) have been synthesized by employing ZIF-67 as precursor for electrochemical supercapacitor and capacitive deionization (CDI). Basically, uniform polyhedral nanocrystals of ZIF-67 were firstly fabricated, and then they were directly subjected to chemical vapor deposition for growing carbon nanotubes. It is found that the as-fabricated HCN electrode exhibits remarkable electrochemical performance, i.e. the highest capacitance of 343 F g−1 at the scan rate of 10 mV s−1 and excellent rate capability. This is due to that HCN can provide rich space and short ion diffusion path. Moreover, the HCN electrodes shows superior CDI performance, i.e. the electrosorption capacity reached as high as 7.08 mg g−1 and the adsorption rate of 0.03958 mg g−1·min−1.