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Graphite@silicon embedded in a carbon conformally coated tiny SiO2 nanoparticle matrix for high-performance lithium-ion batteries
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2021-07-31 , DOI: 10.1039/d1qi00618e
Huitian Liu 1 , Xu Liu 1 , Zhaolin Liu 2 , Junyan Tao 1 , Xiaoqian Dai 1 , Qi Yang 1 , Jikai Xu 1 , Zhongqiang Shan 1
Affiliation  

Engineering of graphite@Si/carbon composites is considered as an effective strategy to surmount the shortcomings of the low conductivity and large volume expansion of bare Si anode materials for lithium-ion batteries. Nevertheless, their applications in high-performance electric vehicles are still challenging owing to their limited accessible capacity. Herein, SiO2 as an active additive was introduced to improve the capacity of graphite@Si/carbon composites. Two different composites, graphite@Si sequentially embedded in SiO2 and carbon layers (G@Si/SiO2 layer/C) and encapsulated in a carbon conformally coated tiny SiO2 nanoparticle matrix (G@Si/SiO2 NPs/C), were well-designed. Both the Si/C composites exhibit a longer cycle life than the graphite@Si/C due to the unique double protective sheath of inert components (Li2O and Li4SiO4) and carbon. The former was formed during the first lithium insertion of SiO2. Specifically, the G@Si/SiO2 NPs/C shows a high specific capacity (607 mA h g−1), exceptional cycling stability (92% retention after 800 cycles at a 0.5 A g−1) and promising rate capability. The remarkable performances benefit from the porous three-dimensional network structure constructed by an amorphous carbon matrix shell and a graphite core, which well disperse and support Si and SiO2, thus improving their electrochemical activity, alleviating the volume change and increasing the Li-ion diffusion effectively.

中文翻译:

石墨@硅嵌入碳保形涂覆的微小 SiO2 纳米颗粒基质中,用于高性能锂离子电池

石墨@Si/碳复合材料的工程化被认为是克服锂离子电池裸Si负极材料导电率低和体积膨胀大的缺点的有效策略。然而,由于其可用容量有限,它们在高性能电动汽车中的应用仍然具有挑战性。在此,SiO 2作为活性添加剂被引入以提高石墨@Si/碳复合材料的容量。两种不同的复合材料,石墨@Si 依次嵌入 SiO 2和碳层(G@Si/SiO 2层/C)并封装在碳共形涂覆的微小 SiO 2纳米颗粒基质(G@Si/SiO 2NPs/C),设计得很好。由于惰性组分(Li 2 O 和 Li 4 SiO 4)和碳的独特双重保护层,两种 Si/C 复合材料都表现出比石墨@Si/C 更长的循环寿命。前者是在 SiO 2的第一次锂插入期间形成的。具体而言,G@Si/SiO 2 NPs/C 显示出高比容量(607 mA hg -1)、出色的循环稳定性(在 0.5 A g -1 下800 次循环后保留 92% )和良好的倍率性能。卓越的性能得益于由无定形碳基壳和石墨核构成的多孔三维网络结构,可以很好地分散和支撑 Si 和 SiO2,从而提高其电化学活性,减轻体积变化并有效增加锂离子扩散。
更新日期:2021-08-19
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