Sulphate Doped Polypyrrole Tin Composite for the Lithium Ion Battery Anode and Its Electrochemical Performance Evaluation

Tin is considered as a promising candidate for the lithium ion anode which is synthesized by co-precipitation technique using stabilizing agents such as C-TAB. The conducting Sn-sulphate doped polypyrrole is synthesized by polymerization of pyrrole monomers in the nano tin particles dispersed in 0.1% PVP + water medium using ammonium per sulphates as a polymerizing as well as doping agent.  The XRD, SEM and TEM analysis confirms the formation of polypyrrole coated on tin nano particles to form a composite. Pulverization effect of tin metal electrode is the highly significant challenge to solve while charge-discharge process, thus while lithium insertion and desertion process the polymer based conductive material like polypyrrole  (conductive polymer) coated on tin nano particle holds the active material to avoid isolation from the conductive matrix, which act as a current collector. The coating thickness is being optimized by the various weight ratios of polymer to tin nano particles from 5 to 20%. The thickness of the coating is analyzed by SEM and TEM; the electrochemical behavior is investigated by EIS and charge-discharge studies. 80:20 ratio of tin-polypyrrole composite gives almost 100% capacity retention at the rate 400 mA g^-1 and delivers initial specific discharge capacity of 878 mAh g^-1