Abstract
Chemical preparation of composite powders of polypyrrole and either 
, 
, or spinel 
has been successfully achieved by injecting liquid pyrrole into an acidic medium containing suspended manganese dioxide powder as an oxidizing agent. The content of manganese dioxide in the composites increased with increasing amount of suspended manganese dioxide in the polymerization bath. The maximum content of manganese dioxide was 85, 87, and 83.3 weight percent for 
, 
, and 
, respectively. Charge‐discharge tests of 
and 
composites conducted in a mixed solvent of propylene carbonate and 1,2‐dimethoxyethane (1:1) containing 1 mol dm−3 
have revealed that the polypyrrole worked well both as an active material and as a conducting network for manganese dioxide. The 
composite gave one potential plateau in both charge and discharge curves, whereas the 
composite exhibited two distinct potential regions. The utilization of manganese dioxide was higher when polypyrrole was used as the conducting matrix than when carbon powder was used. Elemental analyses of the composites have revealed that both electrolyte anions and cations were involved in the charge‐discharge reaction of the 
composite, but electrolyte cations alone were involved in that of the 
/polypyrrole composite. The mechanisms of the charge‐discharge reaction of these two kinds of composites are in good conformity with the mechanism of composite formation.