Synthesis and Characterization of LiFePO[sub 4] and LiTi[sub 0.01]Fe[sub 0.99]PO[sub 4] Cathode Materials

Abstract

Nanocrystalline and doped powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O -edge X-ray absorption near-edge structure (XANES) measurements show that doping induces an increased unoccupied d-state in , resulting in an enhanced p-type semiconductivity. In situ Fe -edge XANES measurements of Ti-doped and undoped electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both and doped cathodes demonstrate good electrochemical performance.