Can silver be a reliable current collector for electrochemical tests

Abstract

The true functionality of a current collector employed in electrochemical cells is to ensure a low-resistance steady electrons flow between the cell and instrumentation without involving in any local electrochemical reactions of the electrode. In this study, we investigated the effect of curing temperature of a common current collector, silver, on the polarization area specific resistance (ASR) of a cathode. The results explicitly showed that at least one order of magnitude lower ASR for a cathode with Ag cured at 800C than that cured at 650C of the same cathode configuration. Microscopic analysis of the 800C-cured cells revealed a deep penetration and abundant distribution of Ag into the cathode/electrolyte interfacial region. These finely dispersed and highly conductive Ag particles/agglomerates areORR(oxygen reduction reaction)-active, thus engaging in the local electrochemical reaction and overshadowing the true properties of the cathode under investigation. Based on these results, we call for caution when using Ag as a current collector for electrochemical measurements, particularly at a temperature 650C. © 2012 The Electrochemical Society.