Synthesis and Characterization of LiFePO(4)–PANI Hybrid Material as Cathode for Lithium-Ion Batteries

This work focuses on the synthesis of LiFePO(4)–PANI hybrid materials and studies their electrochemical properties (capacity, cyclability and rate capability) for use in lithium ion batteries. PANI synthesis and optimization was carried out by chemical oxidation (self-assembly process), using ammonium persulfate (APS) and H(3)PO(4), obtaining a material with a high degree of crystallinity. For the synthesis of the LiFePO(4)–PANI hybrid, a thermal treatment of LiFePO(4) particles was carried out in a furnace with polyaniline (PANI) and lithium acetate (AcOLi)-coated particles, using Ar/H(2) atmosphere. The pristine and synthetized powders were characterized by XRD, SEM, IR and TGA. The electrochemical characterizations were carried out by using CV, EIS and galvanostatic methods, obtaining a capacity of 95 mAhg(−1) for PANI, 120 mAhg(−1) for LiFePO(4) and 145 mAhg(−1) for LiFePO(4)–PANI, at a charge/discharge rate of 0.1 C. At a charge/discharge rate of 2 C, the capacities were 70 mAhg(−1) for LiFePO(4) and 100 mAhg(−1) for LiFePO(4)–PANI, showing that the PANI also had a favorable effect on the rate capability.