A novel approach for extracting contact impedance of electrode/electrolyte interface by minimizing error between impulse response and system function

Abstract

Electrochemical impedance spectroscopy (EIS) is widely used to analyze the electrode/electrolyte interface, but it has the disadvantage of long measurement time. Previous studies reduced this latency by utilizing specific waveforms such as square and dynamic signals. However, these methods can easily lose phase information due to the measurement noise and constrained sampling rate, which compromises the accuracy of impedance calculations. Here, we propose a novel approach to rapidly extract electrochemical properties at the electrode/electrolyte interface using only the magnitude information of measured signals. The proposed method obtains the contact impedance by minimizing the magnitude error between the theoretical system function and the measured impulse response, demonstrating greater resilience to the phase loss. When calculating the difference rate with conventional EIS, the extracted contact resistance and capacitance data exhibit a 10.34 % and 59.24 % improvement, respectively, compared to the previous approach that utilizes the Nyquist plot incorporating phase data.