Accounting for stray capacitances in impedance measuring cells — A mandatory step in the investigation of solid ion conductors

The determination of the dielectric response properties is essential to the investigation of solid ion conductors. The stray capacitance contributions of the measuring cell must be systematically determined and subtracted from the acquired data. Hereby, we report and discuss a general method that can be used for the accurate determination of stray capacitance in impedance measuring cells. Our method can be applied to all commercial or custom-made impedance cells or sample holders used for variable temperature conductivity measurements of fast ion conductors. After the description of the method, we present the experimental calibration done for a 2032-type coin cell sample holder. The 2032-type coin cell is a highly reliable sample holder for impedance measurements of air sensitive materials. We tested the method on a known sample and we validated it by comparing with the results obtained in a simple reference configuration. Our simple, efficient and robust method for the determination of parasitic capacitive contributions may serve as an example of good practice in the field of solid electrolytes, solid state batteries and dielectric materials investigations.