Kinetic studies of the electrochemical reaction between lithium and phthalocyanine II. Reduction reaction mechanism

✍ Scribed by H. Djellab; F. Dalard; D. Deroo; M.B. Armand

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 432 KB
• Volume: 16
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/0378-7753(85)80002-1

✦ Synopsis

The reduction reaction mechanism of metal-free phthalocyanine (H,Pc) in the presence of alkali cations was studied. The chemical lithiation was obtained by reaction with n-butyl lithium. The chromatographic analysis of the chemical products revealed both octane and butane. The presence of butane as a co-product could be due to the hydrogen substitution reaction with n-butyl lithium.

The electrochemical behaviour was studied with evaporated H,Pc thin cathodes on stainless steel with a polyethylene oxide-LiC104 electrolyte. When current flow, the phthalocyanine can partially migrate into the electrolyte. This phenomenon, detected using a microporous nickel foil inserted into the electrolyte, was prevented by coating the HzPc deposit with a thin layer of a polycation.

Thus the reversible capacity given by the topochemical reaction could then be studied rationally.

The present work suggests that the cathodic reduction involves both lithium intercalation and phthalocyanine anion dissolution into the polymer electrolyte.