Abstract
LiFePO4 has attracted attention as a promising cathode material for lithium ion battery, because it
consists of iron which exists abundantly. However, its low electronic conductivity was a problem to use as a
commercial product. The deposition of conductive carbon on the surface of LiFePO4 (LiFePO4/C) is the main
method to improve the electronic conductivity of it. Furthermore, gold, which has higher electronic
conductivity than carbon, has been studied to attach the surface of LFP to increase the electronic conductivity.
However, direct attachment of Au on LFP surface leads to low battery performance because gold disturbed Li+
insertion/deinsertion. Therefore, we synthesized Au or Pd nanoparticles on LiFePO4/C. 0.1mM Au[III]
solution and 0.5 mM Pd[II] solution were irradiated with LiFePO4/C by 200 kHz-ultrasound for 20 minutes in
Ar atmosphere. 2-propanol was added into the solution before the ultrasound irradiation. As a result, the size of
Au nanoparticles was ‹ 10 nm and Pd nanoparticles were agglomerated (the size of secondary particles was
20-30 nm). Especially, Au nanoparticles existed in the carbon layer. LiFePO4/C·Au and LiFePO4/C·Pd showed
good battery performances at high current density (10 C).
