Polypyrrole-controlled plating/stripping for advanced zinc metal anodes

Abstract Zinc metal as anodes has been widely used for electrochemical energy storage devices using aqueous electrolytes, due to its cost effective, eco-friendliness, as well as low redox potential in aqueous solutions. However, Zn prefers to grow into plate-like structures that vertically stand on current collectors. They protrude toward separators or break during cycles, thereby provoking internal short circuit and/or poor cycling stability. Here, polypyrrole is exploited to manipulate the nucleation/growth of zinc via the interaction between –NH and Zn2+. The resultant Zn microplates grow nearly parallel to the current collector, effectively avoiding the negative effects. The performances of PPy-coated Zn as the anode are greatly improved, as demonstrated in symmetric PPy-coated Zn//PPy-coated Zn, PPy-coated Zn//active carbon and PPy-coated Zn//δ-MnO2. Especially for PPy-coated Zn//active carbon, it can stably run at 5 A g−1 for 12,000 cycles with a capacity retention of 96%. The results indicate the promising potential of conductive polymers in advanced zinc anodes.