Three-Dimensional Silicon/Carbon Core-Shell Electrode As an Anode Material for Lithium-Ion Battery

The high-performance materials used for lithium ion batteries include Si-based materials which are some of the most promising materials for electrodes in large rechargeable batteries because of their exceptionally high gravimetric capacity (3,572 mAh/g), low redox potential between 0.2 and 0.4 V (vs. Li/Li⁺) and low reactivity with non-aqueous electrolyte. Practical application of silicon anodes with huge capacity for lithium ion batteries has so far been mainly hindered due to its low electrical conductivity and large volume change (ca. 400 %) generating during the lithiation and delithiation process [1]. Thus, surface engineering for particles (active material design) and modification for electrode structure (electrode design) of silicon are necessary to alleviate these critical limiting factors. The silicon/carbon core-shell particles (Si@C, active material design) were prepared by thermal chemical vapor deposition and subsequent three-dimensional electrode (electrode design) with channel width of 30 µm using laser technique. The electrochemical characteristics of three-dimensional Si@C employed as anode material for lithium-ion batteries were investigated in order to find effects of material and electrode design. The introduction of carbon coating and laser structuring was achieved the enhanced performance of Si anode materials exhibiting high specific capacity (>2,000 mAh/g), good rate capability and stable cycling (>95% over 50 cycles). The morphology of core-shell having 3D channel could minimize the volume expansion by adoption of void space during repeated cycling.

[1] D. Larcher, S. Beattie, M. Morcrette, K. Edström, J.-C. Jumas and J.-M. Tarascon, J. Mater. Chem. , 17, 3759 (2007).