PERFORMANCE OF THE LOW-CURRENT-DENSITY-SYNTHESIZED POLYPYRROLE IN LITHIUM CELLS CONTAINING PROPYLENE CARBONATE

The properties of polypyrrole (PPy) films synthesized at very low current densities (1–250 µA/cm2) were investigated. Potentiodynamic cycling, in situ FTIR spectroscopy, and in situ differential electrochemical mass spectroscopy were employed. The use of propylene carbonate (PC) based electrolytes for the synthesis results in an incorporation of PC fragments (arising by the electro-oxidation of PC) into the grown polypyrrole film. During subsequent cycling of PPy films in 0.5M LiClO4/PC electrolyte, the electrochemical oxidation of PC proceeds parallel with the doping/undoping process. The decrease in current density during polymer growth has the same effect as an addition of small amounts of water into the electrolyte for synthesis—the performance of the polymer in secondary lithium cells is improved. © 1990, The Electrochemical Society, Inc. All rights reserved.