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Toward Understanding of Electrical Limitations (Electronic, Ionic) in LiMPO[sub 4] (M=Fe, Mn) Electrode Materials

2005; Institute of Physics; Volume: 152; Issue: 5 Linguagem: Inglês

10.1149/1.1884787

1945-7111

Charles Delacourt, Lydia Laffont, Renaud Bouchet, Călin Wurm, J.‐B. Leriche, Mathieu Morcrette, J.‐M. Tarascon, Christian Masquelier,

Supercapacitor Materials and Fabrication

To better understand the factors responsible for the poor electrochemical performances of the olivine-type , various experiments such as chemical delithiation, galvanostatic charge and discharge, cyclic voltamperometry, and impedance conductivity, were carried out on both and . Chemical delithiation experiments confirmed a topotactic two-phase electrochemical mechanism between and the fully delithiated phase (, , and ). We conclude that the limiting factor in the / electrochemical reaction is nested mostly in the ionic and/or electronic transport within the particles themselves rather than in charge transfer kinetics or structural instability of the phase. For instance, the electrical conductivity of ( at 573 K, ) was found to be several orders of magnitude lower than that of ( at 298 K, ).