Possibility of modification of phosphoolivine by substitution in Li sublattice

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• 作者：Andrzej Kulka ; Anna Milewska ; Wojciech Zaj?c ; Konrad ?wierczek ; Emil Hanc ; Janina Molenda
• 关键词：Li-ion batteries ; LiFePO4 ; Cathode materials ; Doping
• 刊名：Solid State Ionics
• 出版年：2012
• 出版时间：4 October, 2012
• 年：2012
• 卷：225
• 期：Complete
• 页码：575-579
• 全文大小：949 K

文摘

Possibility of substitution of Li⁺ by Al³⁺, Zr⁴⁺ or W⁶⁺ and its influence on physicochemical properties of LiFePO₄ phosphoolivine was investigated by means of XRD, SEM/EDS, electrical conductivity and Seebeck coefficient measurements. The possible range of solid solution formation in Li_1 ? 3xAl_xFePO₄, Li_1 ? 4xZr_xFePO₄ and Li_1 ? 6xW_xFePO₄ doped phospoolivines was found to be very narrow. Transport properties of the synthesized materials were found to be rather weakly dependent on the assumed chemical composition. No increase of electrical conductivity of the doped samples was observed. The battery performance of selected olivines was tested by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Comparing to Li_0.97Al_0.01FePO₄ and Li_0.96Zr_0.01FePO₄, Li_0.94W_0.01FePO₄ material performed significantly worse, which may be attributed to the presence of a secondary phase and blocking of Li-ion transport paths by dopant.