Synthesis and Properties of Novel Sulfide-Containing Aniline Copolymers as a Cathode Material for Li-Ion Batteries

A novel sulfide-containing aniline, 4-amino-dihydrobenzothiophene (ADBT), is synthesized by the alkylbromination of 1,2-dimethyl-3-nitrobenzene. Copolymers of aniline and ADBT, P(An-co-ADBT), are prepared by chemical oxidative polymerization and tested as a cathode material for Li-ion batteries. The results show that the copolymerization activity of ADBT is lower than that of aniline. The charge/discharge tests show that the P(An-co-ADBT)-2 gives well-defined and sloping plateaus in the potential rang of 3.0–4.0 V and quite a high capacity of 104.7 mAh g −1 . The P(An-co-ADBT)-2 also shows high cycling stability and coulombic efficiency. After 50 cycles, the discharge capacity of the P(An-co-ADBT)-2 still maintains 87.8% of the capacity obtained at the initial cycle.