Walnut-structure Si–G/C materials with high coulombic efficiency for long-life lithium ion batteries |
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Authors: | Chengmao Xiao Peng He Jianguo Ren Min Yue Youyuan Huang Xueqin He |
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Affiliation: | BTR New Energy Materials Inc, Shenzhen 518106 P. R. China, |
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Abstract: | Nano-sized silicon is a potential high energy density anode material for lithium ion batteries. However, the practical use of a nano-Si anode is still challenging due to its low coulombic efficiency, poor scalability and cycling stability. Herein, a Si/graphite/carbon (Si–G/C) composite with a core–shell structure was fabricated by a facile two-step chemical process, stirring–evaporating followed by heat treatment. The composite structure consists of a graphite core, coated first by silicon and then amorphous carbon, which was decomposed by pitch. The as-prepared Si–G/C composite anode demonstrates a first cycle capacity of about 650 mA h g−1, over 90% coulombic efficiency, and high capacity retention of 96.7% after 50 cycles. When paired with a commercial NCA cathode, superior cycling stability with more than 81% capacity retention was achieved for 1200 cycles. These results demonstrate that such a core–shell Si–G/C composite is a promising anode material for high energy Li-ion batteries.Nano-sized silicon is a potential high energy density anode material for lithium ion batteries. |
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