Electrochemical study on polypyrrole microparticle suspension as flowing anode for manganese dioxide rechargeable flow battery

Comparison study on the electrochemical behaviors of PPy microparticle suspension and PPy film in the electrolytic solution of MnSO4 + H2SO4 has been done. The cyclic voltammogram of PPy suspension is almost similar to that of PPy film, suggesting the feasibility of charge transfer between the conductive substrate and PPy particles dispersed in the solution. The electrochemical response of PPy microparticle suspension in flowing mode obviously differs from that under static state, exhibiting good charge transfer property, therefore PPy microparticle suspension is used to fabricate PPy suspension//manganese dioxide rechargeable flow battery. The present system exhibits a significant improvement on the capacity density and cycle performance in comparison with PPy-based film batteries. The discharge capacity density of PPy reaches 132.3 mA h g(-1), and it still remains 97.2% of original value after 90 cycles. The coulombic efficiency shows no significant change with an average value of 92.1% over the experiment. Moreover, the system in the flow mode shows the improved discharge current, which reaches 15 mA cm(-2). (C) 2013 Elsevier B.V. All rights reserved.