Repeatability of low scan rate cyclic voltammetry in bioelectrochemical systems and effects on their performance

Background Cyclic voltammetry (CV) has become a standard tool in the study of bioelectrochemical systems (BES) because it is a nondestructive technique that provides useful information on the electron transfer capacity of these systems. When applied to the large‐surface electrodes typically found in BES, the scan rate must be severely diminished or otherwise the capacitive current masks the faradaic current. Decreasing the scan rate results in an increase in the duration of the experiments, which can lead to a significant alteration of the initial system conditions. Results The repeatability of low scan rate cyclic voltammetry (LSCV) in air cathode microbial fuel cells (AC‐MFCs) operating in batch mode was examined. Consecutive LSCVs at 0.1 mV s−1 were recorded with and without prior renewal of the culture medium. Significant deviations in CV replicates were observed when the medium was not replaced (as high as 40% of maximum intensity). These deviations decreased (