Correlation of Overvoltages and Current Densities to Estimate Optimal Electrode Size for Sediment Microbial Fuel Cells

Abstract

Abstract We propose a method to determine the optimal electrode size of sediment microbial fuel cells (SMFCs). Four SMFCs presented a proportional increase in the current to the electrode size of the MFCs at day 16. From the I–V curves of the SMFCs, four plots of current versus electrode size ( I–E size plots) were obtained, which displayed high R 2 values ranging from 0.980 to 0.994. At day 47, however, V–I curves deviated in one of the four MFCs, such that the I–E size plots obtained from the I–V curves were inappropriate for estimating the electrode size. We found that the curves of overvoltage against the current density ( η–j curves) were comparable in the SMFCs, suggesting that the overvoltage is inversely proportional to the electrode size of the MFCs. The I–E size plots corrected by using the η–j curves had high R 2 values of over 0.978, indicating that the η–j curves can be used for estimating the electrode size when the working voltage to current density ratio is different in SMFCs.

Key findings

• ▸A proportional increase in current to electrode size was observed in SMFCs at day 16.
• ▸High R² values (0.980-0.994) were obtained from I-E plots at day 16.
• ▸Overvoltage is inversely proportional to electrode size, as shown by comparable η-j curves in SMFCs.

Keywords

Identifiers

DOI

10.1002/ente.201500272

Journal

Energy Technology

Year

2015