THE INFLUENCE OF THE POROUS STRUCTURE, MICROKINETICS AND DIFFUSION PROPERTIES ON THE CHARGE-DISCHARGE BEHAVIOR OF CONDUCTING POLYMERS

For different samples of poly(anyline) (PAni) and poly(paraphenylene) (PPP) impregnated with electrolyte solutions the real (swelled) struct ure was measured. The swelled (PAni) and PPP films and powders show an appreciable internal porosity (some tens %) and a high internal surfa ce (250-600 m(2)/g). The main range of pore radii is between 1 and 10( 2)-10(3) nm. The mean radius of single nonporous fibrils is 2-7 nm for PAni and 4-19 nm for PPP. The doping degree, the nature of the counte rions and the method of preparation (chemical or electrochemical) have a considerable influence upon the porous structure. On the base of th ese data a model for the behaviour of electrodes from conducting polym ers was established. An investigation of the kinetic behaviour of such electrodes gives the possibility to assess the intrinsic values of so me important parameters: diffusion coefficients of counterions in the solid polymer phase, exchange current density of the doping-undoping r eactions and the specific capacity of the polymer/electrolyte interfac e Copyright (C) 1996 Elsevier Science Ltd.