Particle-size effects on the entropy behavior of a LixFePO4 electrode.
The particle-size effects on the thermodynamic properties and kinetic behavior of a Li(x)FePO(4) electrode have a direct influence on the electrode properties. Thus, the development of high-performance Li-ion batteries containing a Li(x)FePO(4) cathode requires a complete understanding of the reaction mechanism at the atomic/nano/meso scale. In this work, we report electrochemical calorimetric and potentiometric studies on Li(x)FePO(4) electrodes with different particle sizes and clarify the particle-size effect on the reaction mechanism based on the entropy change of (de)lithiation. Electrochemical calorimetry results show that a reduction in particle size shrinks the miscibility gap of Li(x)FePO(4) while potentiometric measurements demonstrate that the Li(x)FePO(4) particles equilibrate into either a kinetically metastable state or a thermodynamically stable state depending on the particle size.
Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656 (Japan).
Kazuhiko
K
Kai
Yo
Y
Kobayashi
Hajime
H
Miyashiro
Gosuke
G
Oyama
Shin-Ichi
S
Nishimura
Masashi
M
Okubo
Atsuo
A
Yamada
calorimetry; electrode materials; entropy; lithium-ion battery; phase separation