Challenges and limitations of using charge storage capacity to assess capacitance of biomedical electrodes

•Charge storage capacity is routinely applied to characterize biomedical electrodes.•Experimental conditions (potential range, scan rate and oxygen content) affect CSC.•Overestimation/underestimation of CSC values is a common problem.•An urgent need for a standardization of CSC measurements is highlighted. A rapid progress in the field of bioelectronics has enforced to develop standardized performance tests for electrodes serving as tissue interfaces. One of the most routinely applied tests comprises the determination of a charge storage capacity (CSC), which is a parameter used to assess the amount of charge than can be stored within the electrode material. The aim of this work was to indicate challenges and limitations of a current method used to measure CSC, which is based on cyclic voltammetric measurements under arbitrarily chosen experimental conditions, and the risks of overestimation/underestimation of determined capacitance values. Acknowledging the necessity to develop standardized performance tests applicable in bioelectronics, we have provided a set of guidelines for selecting experimental conditions suitable for a reliable CSC analysis.