Preparation and Properties of LiF-doping LiFePO4/C Anode Material

Abstract

LiFe(PO4)1–x F x /C was successfully composited using a mechanical activation-carbon thermal reduction process using LiF as the doped fluoride source, and x was 0.01, 0.02, 0.03, 0.04. In this article, material testing used scanning electron microscopy, X-ray crystal diffraction analysis, specific surface area analysis, cyclic voltammograms, and the ac impedance test. The results showed that when x = 0.03, LiFe(PO4)0.97F0.03/C material showed good capability in regard to charge and discharge, and cycle performance was good. The specific surface area was 84.27 m2/g, which was created by the mechanical activation-carbon thermal reduction process. The initial discharge of LiFePO4 synthesized under such conditions was 153.278 mA h/g (0.1C and 2.5–4.2 V). Compared with less doped LiFePO4/C material, the discharge-specific capacity of the material was 127.351 mA h/g under the same conditions. This increases by 20.34% for the initial time cycle, and after 20 circulations, the capacity was 151.512 mA h/g.