Abstract
Coke powder activated carbon (CPAC) was prepared by dipping-calcined KOH activation method. Using CPAC as the raw material a series of composite electrode materials of CPAC/α-Co(OH)2 with different mass fractions of cobalt were synthesized by the Sol–gel method. The physical properties of the resulting samples were characterized by the field emission scanning electron microscopy and the X-ray diffraction. The results show that composite materials, CPAC/α-Co(OH)2, have a flower-like structure. The results of electrochemical performances show that the composite material has a good electrochemical capacity of 472.3 F g−1 with a cobalt doping amount of 30 wt %. By the cyclic voltammetry testing, we found that the anodic peak potential of the redox peaks in composite electrode materials shifted positively when the scan rate increased, while the cathodic peak potential shifted negatively, and that would cause a gradual increase of the peak potential difference of redox peaks. In contrast, the lower of the scan rate, the smaller of the peak potential difference and the better of the reversibility of composite material. The results of impedance testing show that CPAC/α-Co(OH)2 has a lower electrochemical impedance than that of CPAC.
Highlights
As a kind of new energy store and conversion equipment, electrochemical supercapacitors (ECs) have generated great interests due to their large capacitance, long cycle life and quick charge/discharge performance, etc. [1–4]
By the cyclic voltammetry testing, we found that the anodic peak potential of the redox peaks in composite electrode materials shifted positively when the scan rate increased, while the cathodic peak potential shifted negatively, and that would cause a gradual increase of the peak potential difference of redox peaks
Based on the energy store mechanism, electrochemical supercapacitors can be separated into two different categories: electric double layer capacitors (EDLCs) and redox pseudocapacitors [5–7]
Summary
As a kind of new energy store and conversion equipment, electrochemical supercapacitors (ECs) have generated great interests due to their large capacitance, long cycle life and quick charge/discharge performance, etc. [1–4]. Based on the energy store mechanism, electrochemical supercapacitors can be separated into two different categories: electric double layer capacitors (EDLCs) and redox pseudocapacitors [5–7]. Several kinds of porous carbon materials [11–15] have been widely applied in the electrochemical double-layer capacitors (EDLCs), owing to characteristics of abundant raw materials, low production cost, high special surface area, higher electrochemical stability, better electrical conductivity, and so on. One can build the electrochemical supercapacitors, which have the advantages of both of electric double layer capacitors (EDLCs) and redox pseudocapacitors [16, 17]. Considering the low cost and excellent capacitance, the cobalt compounds have been widely used as electrode materials [18, 19]. The physics and electrochemical performances of the composite electrode materials were systematically investigated. A platinum gauze electrode and a saturated calomel electrode (SCE) were served as the counter electrode and the reference electrode, respectively, and KOH solution (2 mol L-1) was used as the electrolyte
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Materials Science: Materials in Electronics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
