Dispersed polypyrrole latex as a cathode material for all-solid state lithium batteries

Fine bare polypyrrole latex (200 nm sized) was obtained by improved synthesis conditions. This new electronically conducting electroactive material was dispersed in a polyoxyethylene solid salt solution and used as a battery cathode together with a polymer electrolyte film and a lithium sheet in a three-layered system. The resulting battery behaves very well at low current densities though an incomplete dispersion of the latex has been seen from studies on symmetrical cells (using latex composite for both electrodes). A self-discharge problem for the lithium cells arose only before the first discharge and during subsequent charge processes. a previously described theoretical model was used to estimate the ionic diffusion coefficient within the polypyrrole particles. The very low value - 10(-13) cm(2).s(-1) - obtained explains the poor performances of this material at moderate current densities.