Effect of silicon crystallinity on electrochemical performance for chemical vapor deposited silicon-carbon composites

doi:10.11949/0438-1157.20250494

Abstract

Abstract:

Silicon, as a new generation anode material for high-energy-density lithium-ion batteries, is a key technological path for its commercial application by combining it with carbon materials to construct core-shell silicon-carbon materials. Achieving precise control over the morphology of silicon grains is one of the challenges in the current industrial-scale mass production of silicon-carbon materials. Silicon was uniformly deposited into a porous carbon matrix via chemical vapor deposition (CVD), followed by modulating the crystallinity of silicon through controlled carbon encapsulation temperatures. Systematic characterization revealed that Raman spectroscopy exhibits superior sensitivity and accuracy over X-ray diffraction in quantifying silicon crystallinity. The carbon encapsulation temperature was found to exert a significant influence on the crystallinity of silicon, with elevated crystallinity levels markedly degrading the overall electrochemical performance. Specifically, elevation of carbon encapsulation temperature from 550℃ to 800℃ induced a 55.7% capacity loss (1599→709 mAh·g^-1) and 10.65% efficiency decay (91.62%→80.97%) in initial cycling, quantitatively demonstrating the crystallinity-dependent degradation mechanism in silicon-carbon anodes. These findings confirm that Raman spectroscopy serves as a precise diagnostic tool for optimizing CVD process parameters, enabling high-precision consistency control in the mass production of high-performance, low-crystallinity silicon-carbon anodes.

Key words: electrochemistry, composite materials, powders, silicon anode, CVD silicon-carbon, Raman spectroscopy, lithium-ion batteries

摘要：

硅作为高能量密度锂离子电池的新一代负极材料，其商业化应用的关键技术路径之一是与碳材料复合构建核壳结构的硅碳材料。如何实现硅晶粒形态的精确控制是当前硅碳材料产业化量产过程中的难题之一。采用化学气相沉积法将纳米/亚纳米尺寸硅均匀沉积在多孔碳基体中制备气相沉积硅碳复合材料，通过调控最终碳层封装温度实现了硅结晶度的可控调节。结果表明，拉曼光谱技术较X射线衍射方法在硅结晶度表征方面具有更高的灵敏度与准确率优势；碳层封装温度影响硅碳中硅的结晶度水平，硅结晶度升高会对材料的整体电化学性能有负面影响。碳层封装温度在550℃时制备的硅碳表现出1599 mAh·g^-1的首圈放电容量和91.62%的首次库仑效率，升高到800℃时降低到了709 mAh·g^-1和80.97%。研究结果为气相沉积硅碳材料量产过程实现硅结晶度的准确控制提供了可靠方法，可实现高性能低结晶度硅碳负极量产过程中的高精度一致性管控。

关键词: 电化学, 复合材料, 粉体, 硅负极, 气相沉积硅碳, 拉曼光谱, 锂离子电池

CLC Number:

TB 34

Xinye YUAN, Xianbo XING, Denghua LIU, Weitao DING, Borui FAN, Hua ZHONG, Kai HAN. Effect of silicon crystallinity on electrochemical performance for chemical vapor deposited silicon-carbon composites[J]. CIESC Journal, 2025, 76(12): 6708-6717.

袁新烨, 邢显博, 刘登华, 丁伟涛, 范博瑞, 钟华, 韩凯. 气相沉积硅碳中硅结晶度对电化学性能的影响[J]. 化工学报, 2025, 76(12): 6708-6717.

Figures/Tables 8

Fig.1 Schematic diagram of the preparation of silicon-carbon composite materials via CVD: (1) The process involves flowing silane gas, thermally decomposing it, and depositing silicon into the porous carbon structure; (2) Thermally driven carbon deposition from a gaseous precursor to form an encapsulating layer

Fig.2 SEM images, EDS elemental mapping, and TEM characterization analysis of silicon-carbon materials

Table 1 Particle size of silicon-carbon

样品	粒度/μm
样品	D₁₀	D₅₀	D₉₀
Si@C-550℃	4.1	7.8	13.4
Si@C-600℃	4.1	7.7	13.5
Si@C-700℃	4.0	7.9	14.0
Si@C-800℃	3.8	7.7	13.8

Fig.3 XPS spectra of Si@C-550℃ and Si@C-800℃

Fig.4 (a) The XRD patterns of Si@C; (b) Powder electrical resistivity; (c) Raman spectroscopy; (d) Deconvolution and fitting of the first-order Raman characteristic peak of silicon; (e) The crystallization rate of silicon; (f) The ID/IG ratio of carbon in silicon-carbon

Fig.5 Electrochemical performance of Si@C

Table 2 Coulomb efficiency of silicon-carbon at different charging voltages

样品	首圈放电比容量/(mAh·g^-1)	库仑效率
样品	首圈放电比容量/(mAh·g^-1)	0.8 V	1.0 V	1.5 V
Si@C-550℃	1599	79.98%	86.96%	91.62%
Si@C-600℃	1586	79.02%	85.83%	91.04%
Si@C-700℃	1354	75.34%	82.98%	88.68%
Si@C-800℃	709	64.77%	73.94%	80.97%

Fig.6 (a) dQ/dV curve of the first charge-discharge cycle; (b) EIS Nyquist plot; (c) GITT curves and DLi+; (d) and (e) the DLi+vs voltage profiles during discharge and charge, respectively

References 36

[1]	Goodenough J B, Kim Y. Challenges for rechargeable batteries[J]. Journal of Power Sources, 2011, 196(16): 6688-6694.
[2]	Zhong H, Liu D H, Yuan X Y, et al. Advanced micro/nanostructure silicon-based anode materials for high-energy lithium-ion batteries: from liquid- to solid-state batteries[J]. Energy & Fuels, 2024, 38(9): 7693-7732.
[3]	Zülke A, Korotkin I, Foster J M, et al. Parametrisation and use of a predictive DFN model for a high-energy NCA/gr-SiO _x battery[J]. Journal of the Electrochemical Society, 2021, 168(12): 120522.
[4]	Cheng Z L, Jiang H, Zhang X L, et al. Fundamental understanding and facing challenges in structural design of porous Si-based anodes for lithium-ion batteries[J]. Advanced Functional Materials, 2023, 33(26): 2301109.
[5]	Li Z L, Yang Y Z, Wang J, et al. Sandwich-like structure C/SiO _x @graphene anode material with high electrochemical performance for lithium ion batteries[J]. International Journal of Minerals, Metallurgy and Materials, 2022, 29(11): 1947-1953.
[6]	Qi Y, Wang G, Li S, et al. Recent progress of structural designs of silicon for performance-enhanced lithium-ion batteries[J]. Chemical Engineering Journal, 2020, 397: 125380.
[7]	邱治文, 吴爱民, 王杰, 等. Si基锂离子电池负极材料研究进展[J]. 化工进展, 2021, 40(S1): 253-269.
	Qiu Z W, Wu A M, Wang J, et al. Research progress of Si-based anode materials for Li-ion battery[J]. Chemical Industry and Engineering Progress, 2021, 40(S1): 253-269.
[8]	McDowell M T, Lee S W, Harris J T, et al. In situ TEM of two-phase lithiation of amorphous silicon nanospheres[J]. Nano Letters, 2013, 13(2): 758-764.
[9]	Chae S, Choi S H, Kim N, et al. Integration of graphite and silicon anodes for the commercialization of high-energy lithium-ion batteries[J]. Angewandte Chemie International Edition, 2020, 59(1): 110-135.
[10]	Jin Y, Li S, Kushima A, et al. Self-healing SEI enables full-cell cycling of a silicon-majority anode with a coulombic efficiency exceeding 99.9%[J]. Energy & Environmental Science, 2017, 10(2): 580-592.
[11]	程伟江, 汪何琦, 高翔, 等. 锂离子电池硅基负极电解液成膜添加剂的研究进展[J]. 化工学报, 2023, 74(2): 571-584.
	Cheng W J, Wang H Q, Gao X, et al. Research progress on film-forming electrolyte additives for Si-based lithium-ion batteries[J]. CIESC Journal, 2023, 74(2): 571-584.
[12]	Zhang Y X, Wu B R, Mu G, et al. Recent progress and perspectives on silicon anode: synthesis and prelithiation for LIBs energy storage[J]. Journal of Energy Chemistry, 2022, 64: 615-650.
[13]	Yao Y, McDowell M T, Ryu I, et al. Interconnected silicon hollow nanospheres for lithium-ion battery anodes with long cycle life[J]. Nano Letters, 2011, 11(7): 2949-2954.
[14]	Huang X, Cen D C, Wei R, et al. Synthesis of porous Si/C composite nanosheets from vermiculite with a hierarchical structure as a high-performance anode for lithium-ion battery[J]. ACS Applied Materials & Interfaces, 2019, 11(30): 26854-26862.
[15]	Salah M, Hall C, Alvarez de Eulate E, et al. Compressively stressed silicon nanoclusters as an antifracture mechanism for high-performance lithium-ion battery anodes[J]. ACS Applied Materials & Interfaces, 2020, 12(35): 39195-39204.
[16]	Pang D, Weng W, Zhou J, et al. Controllable conversion of rice husks to Si/C and SiC/C composites in molten salts[J]. Journal of Energy Chemistry, 2021, 55: 102-107.
[17]	Wang W, Kumta P N. Nanostructured hybrid silicon/carbon nanotube heterostructures: reversible high-capacity lithium-ion anodes[J]. ACS Nano, 2010, 4(4): 2233-2241.
[18]	孙国庆, 李海波, 丁志阳, 等. 硅基负极材料的研究进展[J]. 化工学报, 2025, 76(7): 3197-3211.
	Sun G Q, Li H B, Ding Z Y, et al. Research progress of silicon-based anode materials[J]. China Industrial Economics, 2025, 76(7): 3197-3211.
[19]	Li H D, Li H Y, Lai Y Z, et al. Revisiting the preparation progress of nano-structured Si anodes toward industrial application from the perspective of cost and scalability[J]. Advanced Energy Materials, 2022, 12(7): 2102181.
[20]	Sun C, Sun L, Zhang Y X, et al. Reduced graphene oxide-modified NiCo-phosphates on Ni foam enabling high areal capacitances for asymmetric supercapacitors[J]. Journal of Materials Science & Technology, 2021, 90: 255-263.
[21]	Bai L Q, Zhang Y H, Tong W S, et al. Graphene for energy storage and conversion: synthesis and interdisciplinary applications[J]. Electrochemical Energy Reviews, 2020, 3(2): 395-430.
[22]	Shen X H, Tian Z Y, Fan R J, et al. Research progress on silicon/carbon composite anode materials for lithium-ion battery[J]. Journal of Energy Chemistry, 2018, 27(4): 1067-1090.
[23]	Zhao Y J, Ding C H, Hao Y N, et al. Neat design for the structure of electrode to optimize the lithium-ion battery performance[J]. ACS Applied Materials & Interfaces, 2018, 10(32): 27106-27115.
[24]	Keles O, Karahan B D, Eryilmaz L, et al. Superlattice-structured films by magnetron sputtering as new era electrodes for advanced lithium-ion batteries[J]. Nano Energy, 2020, 76: 105094.
[25]	Quan L J, Su Q L, Lei H Z, et al. Integrated prelithiation and SEI engineering for high-performance silicon anodes in lithium-ion batteries[J]. National Science Review, 2025, 12(7): nwaf084.
[26]	Baddour-Hadjean R, Pereira-Ramos J P. Raman microspectrometry applied to the study of electrode materials for lithium batteries[J]. Chemical Reviews, 2010, 110(3): 1278-1319.
[27]	Jones R R, Hooper D C, Zhang L W, et al. Raman techniques: fundamentals and frontiers[J]. Nanoscale Research Letters, 2019, 14(1): 231.
[28]	Smit C, Swaaij V, Donker H, et al. Determining the material structure of microcrystalline silicon from Raman spectra[J]. Journal of Applied Physics, 2003, 94: 3582-3588.
[29]	Brenot R, Vanderhaghen R, Drevillon B, et al. Contactless electronic transport analysis of microcrystalline silicon[J]. Thin Solid Films, 1999, 337(1/2): 63-66.
[30]	Ma Z X, Liao X B, Kong G L, et al. Raman scattering of nanocrystalline silicon embedded in SiO₂ [J]. Science in China Series A: Mathematics, 2000, 43(4): 414-420.
[31]	Tsu D, Chao B, Ovshinsky S, et al. Effect of hydrogen dilution on the structure of amorphous silicon alloys[J]. Applied Physics Letters, 1997, 71: 1317-1319.
[32]	Richter H, Wang Z P, Ley L. The one phonon Raman spectrum in microcrystalline silicon[J]. Solid State Communications, 1981, 39(5): 625-629.
[33]	Yue G Z, Lorentzen J D, Lin J, et al. Photoluminescence and Raman studies in thin-film materials: transition from amorphous to microcrystalline silicon[J]. Applied Physics Letters, 1999, 75(4): 492-494.
[34]	Zi J, Büscher H, Falter C. Raman shifts in Si nanocrystals[J]. Applied Physics Letters, 1996, 69: 200-202.
[35]	Wang C D, Li Y, Ostrikov K, et al. Synthesis of SiC decorated carbonaceous nanorods and its hierarchical composites Si@SiC@C for high-performance lithium ion batteries[J]. Journal of Alloys and Compounds, 2015, 646: 966-972.
[36]	Li Y C, Zheng X Y, Cao Z, et al. Unveiling the mechanisms into Li-trapping induced (ir)reversible capacity loss for silicon anode[J]. Energy Storage Materials, 2023, 55: 660-668.