Electrodeposition of polypyrrole for high-performance zinc ion battery

Zinc-ion batteries are considered as promising energy storage devices for large-scale energy storage due to the simple operation, low cost, and high safety, while their performances are determined by the cathode materials’ properties. Polypyrrole (PPy) can be used as the cathode material of zinc-ion battery, however, its poor cyclic stability limits the practical application. Considering the fact that electrolytes containing zinc ions are used in zinc ion batteries, the PPy cathode material has been electrodeposited on carbon cloth (CC) by using ZnSO 4 solution as electrolyte (PPy-ZS/CC). The results show that PPy/CC-ZS exhibits higher specific capacity and cyclic stability than the electrode prepared in NaH 2 PO 4 solution because the participation of ZnSO 4 in the deposition process makes PPy-ZS more suitable for the ZnSO 4 electrolyte of batteries. The specific capacity of the PPy-ZS has been increased by 24 mAh g −1 compared with the capacity of PPy deposited in the NaH 2 PO 4 system; after the 1000-cycle test, the capacity retention is 80%. Furthermore, PPy-ZS’s specific capacity can reach 167 mAh g −1 at 0.05A g −1 when the battery is assembled in 2.0 mol L −1 ZnSO 4 + 70 mmol L −1 NH 4 I electrolyte. After 2000 repeated charge/discharge tests at 4.5 A g −1 , Zn//PPy-I-ZS still maintains 75% of the initial capacity, showing quite good stability. It provides an effective method to improve the performance of PPy-based cathode material in Zn-ion battery.