Electrodeposited polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) free-standing film for lithium secondary battery application

Highly flexible and bendable free-standing polypyrrole-para (toluene sulfonic acid) (PPy-pTS) films were prepared using the electropolymerization method. The films are soft, lightweight, mechanically robust, and highly electrically conductive. The films display a cauliflower-like structure consisting of micron-scale spherical grains, which are related to dopant intercalation in the polymeric chains. The electrochemical behaviour of the free-standing films was examined as cathode against lithium counter electrode. Electrochemical tests demonstrated that the PPy-pTS film with 30 min deposition time exhibited higher discharge capacity (85 mAh g−1) beyond 80 cycles than the PPy-pTS films with 1 h deposition time (76 mAh g−1) and 2 h deposition time (55 mAh g−1) at 0.1 mA cm−2 over a potential range of 2.5–4.3 V. The free-standing films can be used as electrode materials to satisfy the new market demand for flexible and bendable polymer batteries.

► Free-standing polypyrrole-para (toluene sulfonic acid) (PPy-pTS) film.
► The films are soft, lightweight, mechanically robust, and highly electrically conductive.
► Application as cathode material for lithium secondary battery
► PPy-pTS film with 30 min deposition time exhibited higher discharge capacity (85 mAh g−1) beyond 80 cycles than the PPy-pTS films with 1 h deposition time (76 mAh g−1) and 2 h deposition time (55 mAh g−1).