Development of Polyaniline-Iithium Secondary Battery

Abstract

Coin-type lithium secondary batteries using polyaniline as positive electrodes have been developed and commercialized. The technical background of the development and fundamental concept of polymer battery designing were described. Advantages of polyaniline as electrode material were also discussed comparing with other conducting materials. Electrochemical redox reaction of polyaniline in nonaqueous electrolytes was pursued by spectroscopy and QCM (Quartz Crystal Microbalance) method. We concluded the charge-discharge reaction with twb redox peaks in that system should be wholely described as electron acceptor type of doping-undoping reaction of poly(iminophenylene), which differed from protonation mechanism occured in aqueous system. Polyaniline electrodes integrated with current collectors of stainless mesh were electro-chemically fabricated directly from acidic solution of aniline. The reaction was controlled to prepare polyaniline composed of substantially only imino-1,4-phenylene (IP) units, not to include quinonoid configuration of polyaniline nor benzidine. Polyaniline synthesized in the process hereby was aproved to be a new industrial chemical material without toxity by MITI of Japanese Government in 1987. The construction and performances of one of the commercialized polyanilme-lithium secondary batteries (AL 2016) were described in detail. The capacity of the battery AL 2016 was 3. 0 mAh at charging voltage of 3.0 V, and 6.0 mAh at 3.5 V respectively. If more stable electrolyte is available the capacity would be increased twice or more. © 1990, The Chemical Society of Japan. All rights reserved.