摘要
Lithium iron phosphate (LiFePO 4 ) is synthesized by a hydrothermal process using pyrrole as an efficient reducing agent and a subsequent calcination. Observations through a scanning electron microscope and a transmission electron microscope (TEM) show that LiFePO 4 has a diameter and length of 500 nm and 3 μm, respectively. The results of TEM and X-ray diffraction confirm that the structure of LiFePO 4 is orthorhombic olivine. Raman and X-ray photoelectron spectroscopy results indicate that Fe 3+ oxidized from reactant Fe 2+ by air reacts with pyrrole, generating polypyrrole (PPy), and reduces to Fe 2+ . PPy that is generated can also serve as a carbon source in the subsequent calcination. In addition, the electrochemical measurement results show that the energy capacity of calcined LiFePO 4 /PPy is 153 mAh g -1 at 0.2 C. Calcined LiFePO 4 /PPy offers promising cycle-life performance in lithium-ion batteries. © 2012 Elsevier Ltd.