Water based processing of LiFePO₄/C cathode material for Li-ion batteries utilizing freeze granulation

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• 作者：J. Orlenius ; O. Lyckfeldtp> ; p>p>ola.lyckfeldt@swerea.sep> ; K.A. Kasvayee ; P. Johander
• 关键词：Li-ion batteries ; LiFePO4 ; Synthesis ; Freeze granulation ; Aqueous processing
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：1 September, 2012
• 卷：213
• 期：Complete
• 页码：119-127
• 文件大小：1171 K

摘要

A water based solid state synthesis of LiFePO₄ has been conducted by utilizing freeze granulation. Various processing conditions were tested and achieved powder properties were characterized by density, XRD, specific surface area, carbon content, conductivity and SEM. Freeze granulation, a novel method for precursor preparation was shown to be an effective method to provide high degree of homogeneity prior to calcination and high ultimate yield of pure LiFePO₄. Cathodes were manufactured by water based as well as NMP system based tape casting. A commercial LiFePO₄/C powder was also characterized and used to manufacture cathodes as comparison in this study. Charge cycling tests showed promising results with high capacity and long term stability, well in the range of what the commercial powder provided. Post-milling of calcined powder prior to paste preparation for tape casting tended, however, to retard the capacity owing to disturbed carbon distribution and loss of conductivity of the LiFePO₄/C. In comparison with the solvent system for cathode manufacturing, the water based system gave similar cell performance, illustrating the possibility to apply a more environmentally sustainable processing of Li-battery cells.