Can Silver Be a Reliable Current Collector for Electrochemical Tests?

The true functionality of a current collector employed in electrochemical cells is to ensure a lowresistance 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 800◦C than that cured at 650◦C of the same cathode configuration. Microscopic analysis of the 800◦C-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 are ORR (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 ≥650◦C. © 2012 The Electrochemical Society. [DOI: 10.1149/2.010301eel] All rights reserved.