Search

Si electrodes are the most important high capacity substitutes of Li metal and carbon anodes in high energy density Li ion batteries, including those based on sulfur or air cathodes. In this study we examined amorphous columnar structure silicon film anodes prepared by sputtering in rechargeable Li ion battery prototypes based on TiS2 cathodes. The choice of this cathode material enabled focusing on the examination of pre-lithiated Si films as anode candidates in alkyl carbonate electrolyte solutions. The effectiveness of fluoro-ethylene carbonate (FEC) as a co-solvent in alkyl carbonates/LiPF6 solutions for good performance of silicon anodes was exhibited. Hundreds of cycles were demonstrated in full Li ion cells containing these components. The columnar morphology of these anodes is retained after 1000 cycles. Their surface chemistry, measured by EDS and XPS is discussed. The results of this work encourage further R&D efforts toward the use of amorphous silicon films as anodes in advanced rechargeable Li batteries. [ABSTRACT FROM AUTHOR]

The effect of fluorinated ethylenecarbonate (FEC) as a cosolventin alkyl carbonates/LiPF6on the cycling performance ofhigh-voltage (5 V) cathodes for Li-ion batteries was investigatedusing electrochemical tools, X-ray photoelectron spectroscopy (XPS),and high-resolution scanning electron microscopy (HRSEM). An excellentcycling stability of LiCoPO4/Li, LiNi0.5Mn1.5O4/Si, and LiCoPO4/Si cells and areasonable cycling of LiCoPO4/Si cells was achieved byreplacing the commonly used cosolvent ethylene carbonate (EC) by FECin electrolyte solutions for high-voltage Li-ion batteries. The rolesof FEC in the improvement of the cycling performance of high-voltageLi-ion cells and of surface chemistry on the cathode are discussed. [ABSTRACT FROM AUTHOR]