Validity and Reproducibility of Counter Electrodes for Linear Sweep Voltammetry Test in Microbial Electrolysis Cells

The electrode is a key component in a microbial electrolysis cell (MEC) that needs significant improvement for practical implementation. Accurate and reproducible analytical methods are substantial for the effective development of electrode technology. Linear sweep voltammetry (LSV) is an essential analytical method for evaluating electrode performance. In this study, inoculated carbon brush (IB), abiotic brush (AB), Pt wire (PtW), stainless steel wire (SSW), and mesh (SSM) were tested to find the most suitable counter electrode under different medium conditions. The coefficient of variation (Cv) of maximum current (Imax) was the most decisive indicator of the reproducibility test. This study shows that (i) the electrode used in operation is an appropriate counter electrode in an acetate-added condition, (ii) the anode LSV test should avoid the use of Pt wire as counter electrodes, and (iii) PtW is an appropriate counter electrode in cathode LSV in all conditions.