Polyaniline Nanorod Arrays as a Cathode Material for High-Rate Zinc-Ion Batteries

In recent years, aqueous zinc-ion batteries have received extensive attention because of their safety, environmental friendliness, and low cost. However, their poor rate performance due to the slow diffusion kinetics of large electrolyte ions hinders their development. In this study, polyaniline nanorod arrays were prepared by chemical oxidation polymerization in a dilute aniline solution and then used as a cathode material for zinc-ion batteries. Polyaniline nanorod arrays have good contact with the electrolyte, which enable them to make full use of their pseudocapacitance and also promote the diffusion of electrolyte ions, thereby improving the rate performance of zinc-ion batteries. When the current density is 0.1 A g–1, the discharge capacity of polyaniline nanorod arrays is 178.4 mA h g–1. When the current density increases to 1 and 10 A g–1, 84.6 and 63.8% of the capacity are retained, respectively, which is better than the rate performance of the polyaniline film. In addition, a zinc-ion battery based on polyaniline nanorod arrays possesses excellent cycle stability at a current density of 10 A g–1. After 10,000 cycles, the capacity retention is 95.2% and the Coulombic efficiency is maintained at 99.9%.