Xiao Chengmao, He Peng, Ren Jianguo, Yue Min, Huang Youyuan, He Xueqin
BTR New Energy Materials Inc Shenzhen 518106 P. R. China
RSC Adv. 2018 Aug 2;8(48):27580-27586. doi: 10.1039/c8ra04804e. eCollection 2018 Jul 30.
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, 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.
纳米硅是一种有潜力的锂离子电池高能量密度负极材料。然而，由于其库仑效率低、可扩展性差和循环稳定性不佳，纳米硅负极的实际应用仍然具有挑战性。在此，通过一种简便的两步化学工艺，即搅拌蒸发后进行热处理，制备了具有核壳结构的硅/石墨/碳（Si-G/C）复合材料。该复合结构由石墨核组成，首先包覆硅，然后包覆由沥青分解得到的非晶碳。所制备的Si-G/C复合负极首次循环容量约为650 mA h g，库仑效率超过90%，50次循环后容量保持率高达96.7%。当与商用NCA正极配对时，在1200次循环中实现了超过81%的容量保持率的优异循环稳定性。这些结果表明，这种核壳结构的Si-G/C复合材料是一种有前途的高能量锂离子电池负极材料。
