Electrochemical characteristics and impedance spectroscopy studies of nano-cobalt silicate hydroxide for supercapacitor
Abstract
Cobalt silicate hydroxide (Co 3[Si 2O 5] 2[OH] 2) was prepared by chemical method for use in electrochemical capacitors. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests indicate that the material was pure hexagonal phase with uniform nanometer size distribution. Cyclic voltammeter (CV) and galvanostatic charge/discharge measurements show that the cobalt silicate hydroxide-based electrode has stable electrochemical capacitor properties between potential range of 0.1-0.55 V with a maximum specific capacitance of 237 F g -1 in alkaline solution and 95% of capacity efficiency was reached after 150 cycles. Electrochemical impedance spectra (EIS) investigation illustrates that the capacitance of the test electrode was mainly consisted of pseudo-capacitance, which was caused by underpotential deposition of H 3O + at the electrode surface.
- Publication:
-
Journal of Power Sources
- Pub Date:
- 2006
- DOI:
- 10.1016/j.jpowsour.2006.03.041
- Bibcode:
- 2006JPS...161..723Z
- Keywords:
-
- Cobalt silicate hydroxide;
- Supercapacitor;
- Electrochemical impedance spectroscopy