Effect of Polyacenic Semiconductors on the Performance of Olivine LiFePO[sub 4

Abstract

An effective way to improve the conductivity of LiFePO 4 is by the introduction of conductive carbon. The carbon structure is an important component needed to obtain optimal electrochemical performance. In the present work, an Olivine-type LiFePO 4 powder has been synthesized from amorphous Fe 3 (PO 4 ) 2 and Li 3 PO 4 ·1/2H 2 O by solid-state methods. For purposes of comparison, the phenol-formaldehyde resin was added as a carbon precursor to convert the polyacenic semiconductor (PAS). This compound is a form of amorphous carbon with decent carbon structures formed after low heat treatments. The electric conductivity of the synthesized LiFePO 4 /PAS composite has been raised by seven orders of magnitude. The resultant electrochemical performance was tested and lower polarization, higher rate capacity, and better cycling ability were obtained.