Preparation and electrochemical properties of LiNi1/3Co1/3Mn1/3O2–PPy composites cathode materials for lithium-ion battery

Layered LiNi1/3Co1/3Mn1/3O2 was synthesized by co-precipitation method, and a series of polypyrrole–LiNi1/3Co1/3Mn1/3O2 composites were then prepared by polymerizing pyrrole monomers on the surface of LiNi1/3Co1/3Mn1/3O2. The bare sample and composites were subjected to analysis and characterization by the techniques of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the composites were investigated with galvanostatic charge–discharge test and AC impedance measurements, which show that the formed coats of polypyrrole (PPy) significantly decrease the charge-transfer resistance of LiNi1/3Co1/3Mn1/3O2. And the composite containing 2.0 wt% PPy exhibits a good electrochemical performance, its specific discharge capacity is 182 mAh g−1 at 0.1C rate and voltage limits of 2.8–4.6 V, while the capacity of the bare sample is only 134 mAh g−1.