Surface Modification of Over-Lithiated Layered Oxides with PEDOT:PSS Conducting Polymer in Lithium-Ion Batteries

Over-lithiated layered oxide (OLO) materials were coated with a PEDOT:PSS conducting polymer via a simple wet-coating method. The prepared samples were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The electrochemical properties of the samples were determined by galvanostatic testing and electrochemical impedance spectroscopy (EIS). PEDOT:PSS coated cathode materials showed better rate capability and cyclability between 2.0 V and 4.6 V. X-ray photoelectron spectroscopy (XPS) data imply that the improved electrochemical performance of coated OLO is due to the suppression of the formation and growth of the solid electrolyte interface.