APPLICATION AND COMPARISON OF CURRENT INTERRUPTION AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY METHODS TO STUDY A MICROBIAL FUEL CELL

Abstract

In this research, current interruption and electrochemical impedance spectroscopy (EIS) methods are employed to determine the internal resistance of a dual-chambered mixed-culture microbial fuel cell with glucose feed, graphite anode, platinum sheet cathode, and Nafion 117 proton exchange membrane. Potential recovery curves and EIS spectra are obtained under various time intervals and analyzed using proper electrical circuit models. Polarization results show that the maximum output power of the cell is about 380 mW.m⁻² normalized to the cathode surface area. The open circuit potential (OCP) of the cell is about 550 mV, and the value of the short circuit current is 0.35 mA.cm⁻² of the cathode geometric surface area. The results show that the current interruption method can monitor in a rather satisfactory way the electrochemical changes such as variations in internal resistance and interfacial pseudo-capacitance inside the microbial fuel cell during the operation and thus can be employed as an easy-to-set-up electrochemical method to gain valuable data and facilitate the study of low power density devices such as microbial fuel cells.

Keywords:

• current interruption method
• electrochemical impedance spectroscopy (EIS)
• internal resistance
• microbial fuel cell (MFC)
• mixed culture biofilm
• time constant

ACKNOWLEDGMENT

The authors would like to gratefully acknowledge the financial support of the Office of Vice Chancellor in Charge of Research of Tabriz University.

Notes

R _s : Ohm; R _a and R _c : Ohm.cm²; n–a, n–c, and W–n: dimensionless parameters; CPE _a-T and CPE _c-T : Ohm⁻¹.sⁿ.cm⁻²; W-T: Ohm⁻¹.s^0.5, “s” denotes the time in seconds; C _a and C _c : μF cm⁻². The goodness of the EIS fits were checked by the chi-squared statistical estimate the values, which were 0.00023 for 9 h and 0.00011 for 36 h EIS data.