Corrosion Protection of Copper Current Collector Of Lithium-Ion Batteries by Doped Polypyrrole Coatings

The current collector is an important multi-functional component of lithium-ion batteries. However, the degradation of current collectors in organic electrolytes influences the capacity, coulomb efficiency and even service life of the batteries. Thus, it is essential to develop a conductive and protective coating for current collectors. In this paper, polypyrrole (PPy) coatings doped with oxalic acid were electrodeposited by cyclic voltammetry technique to enhance the corrosion resistance of a copper current collector. The electrochemical degradation of the polypyrrole-coated copper was investigated by electrochemical impedance spectroscopy (EIS) at room temperature in an organic electrolyte of lithium-ion batteries. After exposure to the electrolyte for up to 500 h, the charge transfer resistance (Rt) of the polypyrrole-coated copper was ~7 times greater than that of the bare copper, indicating that polypyrrole coatings could improve the corrosion resistance of copper current collectors.