Electrochemical Impedance Analysis for Electrochemical Migration of Screen-printed Silver Wiring Electrodes

Abstract

Electrochemical migration processes on two screen-printed silver wiring electrodes were investigated using electrochemical impedance spectroscopy. The impedance measured immediately after initial growth of silver dendrites on the cathode shows three capacitive loops. A loop in the low frequency range was dependent on the electric double layer capacitance and reaction resistance of electrodeposition of silver and oxygen reduction on the cathode. The capacitive loop diameter in the low frequency range decreased with dendrite growth. A capacitive loop in the middle frequency range was attributed to the dissolution reaction of silver on the anode. Results showed that a capacitive loop in the high-frequency range was related to the interelectrode capacitance between the silver wiring electrodes and the water film’s solution resistance. Curve fitting was performed for the impedance spectra by assuming an equivalent circuit. The calculated impedance spectra showed good agreement with experimental results: the reaction resistances and double layer capacitances varied remarkably with dendrite generation, suggesting that the present silver wiring electrode is applicable to an electrochemical migration monitoring sensor.