A Highly Electroactive Poly(aniline-co-thionine) for Rechargeable Zinc Batteries.

A novel conductive polymer poly(aniline-co-thionine) (PANTHI) was prepared via electrochemical polymerization by introducing redox-active thionine into the polyaniline skeleton to extend its cable length, and then explored as a cathode active material for aqueous zinc-polymer batteries in a mixed solution of ZnCl2 and NH4Cl. Due to that thionine is a phenothiazine derivative without methyl groups, it increases the degree of conjugation of copolymer chains and the Zn-copolymer battery exhibits greatly enhanced discharge specific capacity, energy density, and excellent cycle stability at pH 4.8, compared to Zn-polyaniline batteries. The Zn-PANTHI battery delivers a high specific capacity and energy density of 157.8 Ah kg-1 and 173.6 Wh kg-1, respectively, and retains the coulomb efficiency of about 95.3% over 200 consecutive cycles at a current density of 200 mA g-1. The copolymerization strategy provided an effective method towards synthesizing new conductive aniline-based polymers with other organic redox-active groups for rechargeable batteries, supercapacitors and sensors. [ABSTRACT FROM AUTHOR]