Gravimetric electrochemical voltage spectroscopy: In situ mass measurements during electrochemical doping of the conducting polymer polypyrrole

A new technique is described for direct measurement of mass changes of a conducting polymer electrode during electrochemical cycling. A quartz microbalance is used, with one of its contacts serving as the working electrode. Its high sensitivity permits resolution of mass changes less than 100 ng/cm2. The results demonstrate that on reduction of poly(pyrrole perchlorate), charge compensation is achieved by diffusion of the lithium cation into the polymer and not the perchlorate anion into solution. © 1984 The American Physical Society.