Sn-Based Nanocomposite for Li-Ion Battery Anode with High Energy Density, Rate Capability, and Reversibility

다국어 초록 (Multilingual Abstract)

<P>To design an easily manufactured, large energy density, highly reversible, and fast rate-capable Li-ion battery (LIB) anode, Co-Sn intermetallics (CoSn<SUB>2</SUB>, CoSn, and Co<SUB>3</SUB>Sn<SUB>2</SUB>) were synthesized, and their potential as anode materials for LIBs was investigated. Based on their electrochemical performances, CoSn<SUB>2</SUB> was selected, and its C-modified nanocomposite (CoSn<SUB>2</SUB>/C) as well as Ti- and C-modified nanocomposite (CoSn<SUB>2</SUB>/<I>a</I>-TiC/C) was straightforwardly prepared. Interestingly, the CoSn<SUB>2</SUB>, CoSn<SUB>2</SUB>/C, and CoSn<SUB>2</SUB>/<I>a</I>-TiC/C showed conversion/nonrecombination, conversion/partial recombination, and conversion/full recombination during Li insertion/extraction, respectively, which were thoroughly investigated using <I>ex situ</I> X-ray diffraction and extended X-ray absorption fine structure analyses. As a result of the interesting conversion/full recombination mechanism, the easily manufactured CoSn<SUB>2</SUB>/<I>a</I>-TiC/C nanocomposite for the Sn-based Li-ion battery anode showed large energy density (first reversible capacity of 1399 mAh cm<SUP>-3</SUP>), high reversibility (first Coulombic efficiency of 83.2%), long cycling behavior (100% capacity retention after 180 cycles), and fast rate capability (appoximately 1110 mAh cm<SUP>-3</SUP> at 3<I>C</I> rate). In addition, degradation/enhancement mechanisms for high-capacity and high-performance Li-alloy-based anode materials for next-generation LIBs were also suggested.</P>
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