Improvement in hydrophobicity of olivine lithium manganese iron phosphate cathodes by SiF4 treatment for lithium-ion batteries

• Published in: Solid state ionics Vol. 281; pp. 82 - 88
• Main Authors: Theivanayagam, Murali G., Hu, Terry, Ziebarth, Robin, Santhany, Stacie, Goss, Janet, Maeda, Hideaki, Patel, Avani, Behr, Michael, Lowe, Michael, Leugers, Anne
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2015
• Subjects: Batteries; Cathodes; Energy storage; Inorganic materials; Nanomaterials; Nanomaterials; Batteries; Inorganic materials; Cathodes; Energy storage
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2015.09.012

In this report, we successfully demonstrate a novel SiF4 treatment on lithium manganese iron phosphate cathode (LMFP) that can significantly improve its hydrophobic property. The effect of SiF4 treatment on the structure and hydrophobicity of LMFP powder was studied by X-ray diffraction, Fourier transform infra-red spectroscopy, scanning transmission electron microscopy–energy dispersive X-ray spectroscopy, Karl Fisher titration, and thermo-microbalance gravimetric studies. The SiF4 treated LMFP cathode shows a substantial decrease in moisture adsorption by up to half of the untreated LMFP under ambient conditions. The SiF4-treated LMFP also shows excellent cycle life when cycled in lithium-ion full cells, even after exposing the electrodes to ambient conditions for one day, while the untreated LMFP showed a decrease in cycle life after the same exposure. •Moisture adsorption and structure of untreated and SiF4-treated LMFP cathodes are studied.•SiF4-treated LMFP showed about 40% decrease in moisture adsorption.•SiF4-treated LMFP exhibited improved storage performance in humid conditions.•SiF4-treated LMFP even after air exposure demonstrated stable cycle life performance.