1成果简介
　　硅因其环保性、天然丰富性以及在锂离子电池中具有极高的理论容量，被视为极具潜力的阳极材料。然而，硅阳极在循环过程中体积膨胀严重，这阻碍了其经济可行性。本文，广东工业大学党岱 副教授、季华实验室 张成智等研究人员在《Journal of Power Sources》期刊发表名为“Scalable synthesis of nano silicon-embedded graphite for high-energy and low-expansion lithium-ion batteries”的论文，研究通过将硅纳米颗粒引入稳定的膨胀石墨（EG）/沥青衍生碳结构（EGC）中，采用沥青对EG进行增强处理的技术，解决了这一问题。EGC-Si复合材料通过将硅嵌入EGC基体，形成了一种能够有效应对硅颗粒在循环过程中显著体积变化的耐用结构。
　　此外，EGC-Si的工程化结构通过其多样化的多孔结构和碳框架，既增强了离子扩散，又促进了电子的快速传输。EGC-Si阳极在0.1 A g−1电流密度下展现出699.9 mAh g−1的比容量，并在1.0 A g−1电流密度下保持超过400次循环的稳定性。此外，EGC-Si电极在完全锂化后仅呈现6.6%的体积膨胀率，这归功于其精心设计的EGC结构。这种坚固且高度集成的硅/石墨结构为充分释放硅/碳复合负极在高性能锂离子储能中的潜力提供了有前景的策略。
　　2图文导读 

　　图1. (a) Illustration of the synthesis process for EGC-Si composites. SEM images of (b) EGC and (c) EGC-Si; (d) FIB-SEM image of EGC-Si; (e) EDS mapping images of EGC-Si: carbon (red), silicon (blue), and oxygen (green); (f–g) HRTEM and X-ray Micro-CT images of EGC-Si. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

　　图2. Detailed structural and compositional characterization of EGC-Si and EG/Si/C. (a) The TGA of EGC-Si and EG/Si/C. (b) The Raman spectra and (c) XRD patterns of EGC-Si and EG/Si/C, respectively. (d) The pore size distribution of EGC-Si and EG/Si/C. (e–f) Si 2p high-resolution XPS spectra of EGC-Si and EG/Si/C.

　　图3. (a) Initial five cyclic Voltammetry (CV) curves of EGC-Si at the scan rate of 0.2 mV s−1. (b) The cycle stability of the EGC-Si, EGC-Si-2, EGC-3, and EGC-Si-4 electrodes at 0.1 A g−1. (c) A comparison of the cycling performance between this work and other works. (d) The capacity retention of EGC-Si and EG/Si/C electrode at various rates from 0.1 to 5.0 A g−1. (e) Voltage profiles for the EGC-Si at various rates. (f) Prolonged cycling performance at 1.0 A g−1.

　　图4. Ion storage kinetics analysis electrodes during cycling. (a) The correlation between scan rate (shown on a natural logarithm axis) and peak current in cyclic voltammetry curves for EGC-Si and EG/Si/C at different scan rates. (b) Capacitive contribution ratios at different scan speeds. (c–d) EIS spectrum and the linear relation plots of Zct and ω1/2 of EGC-Si and EG/Si/C electrode at the low-frequency region. (e) GITT curves of EGC-Si. (f) The Li-ions diffusion coefficient of EGC-Si and EG/Si/C at discharge/charge states.

　　图5. (a–c) The morphology and diameter change of a single EGC-Si particle in BL, AFL, and ADL processes. (d) The diameter increment ratio of EGC-Si particle along A, B, and C directions in BL, AFL, and ADL processes. (e) The electrode thickness of EGC-Si and EG/Si/C electrodes in BL and AFL is processed, and the right side is its corresponding swelling ratio. (f) C 1s, O 1s, F 1s, and Si 2p spectra of the EGC-Si and EG/Si/C electrodes.

　　图6. The electrochemical principles and performance of the NCM811//EGC-Si full cell. (a) Schematic representation of the lithium-ion battery full cell with the EGC-Si anode and NCM811 cathode. (b) Cycling area capacity at 0.1 A g−1. (c) The charge and discharge profiles of the EGC-Si anode half-cell, NCM811 cathode half-cell, and NCM811//EGC-Si full cell at 0.1 A g−1, the inset SEM picture pertains to NCM811.
　　3小结
　　综上所述，我们成功合成了EGC-Si结构，其中SiNPs嵌入EG框架内，并通过PC对EG的增强作用进一步强化。这种集成架构提供了坚固且具有韧性的框架，能够适应SiNPs在锂化过程中体积的变化，从而提升结构稳定性。EGC-Si在0.1 A g−1电流密度下展现出649.6 mAh g−1的容量，并具备卓越的稳定性，循环次数达400次。完全锂化后，EGC-Si电极仅表现出6.6%的体积膨胀率，这得益于其精心设计的结构。这种硅/石墨复合材料设计可能为商业应用锂离子电池（LIBs）的高容量合金型负极材料提供新的发展方向。
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