Authors: Ahammed Suhail Odungat | Adil Amin | Fatih Özcan | Doris Segets
Source: ECS Meeting Abstracts (article, 2025-07-11)
Field: Materials Science — Ceramics and Composites

Structural Analysis of Si/C Supraparticles Synthesized via Spray-Drying Using Mercury Intrusion Porosimetry and FIB-SEM Cross-Section Image Analysis Lithium-ion batteries (LiBs) are pivotal in advancing sustainable energy solutions due to their widespread applications in electric vehicles and portable electronics. Silicon, with its exceptionally high theoretical specific capacity, has emerged as a promising anode material to meet the growing demand for higher energy densities. However, its commercialization is hindered by challenges such as rapid capacity fading and low Coulombic efficiency, primarily stemming from the significant volume expansion during lithiation [1,2]. Nanostructured silicon has shown potential in addressing these issues by reducing diffusion lengths and enhancing electrochemical performance. However, their practical implementation faces drawbacks like low packing density, unstable solid-electrolyte interphase, and high interparticle resistance [3]. To overcome these challenges, a novel concept of supraparticles—hierarchically structured micro-meter-sized agglomerates of nanoparticles—has been introduced by Amin et al [4,5]. These supraparticles, synthesized using advanced spray-drying techniques, balance the advantages of nanoscale silicon while mitigating its drawbacks, offering improved tap density, thermodynamic stability, and scalability for commercial applications. The microstructure of supraparticles plays a pivotal role in enhancing the performance of Si/C as a battery anode material, influencing critical factors such as the contact between active sites and the electrolyte, as well as lithium-ion diffusion through the catalyst layer. However, a significant knowledge gap remains regarding the detailed microstructural features of supraparticles and how these features can be effectively tuned through synthesis parameters. This study focuses on the comprehensive microstructural characterization of supraparticles synthesized under varying processing conditions and precursor particle sizes, aiming to establish clear relationships between synthesis parameters, particle morphology, and internal microstructure. To achieve this, advanced microstructural analysis techniques, including mercury intrusion porosimetry (MIP) and a custom-developed image analysis algorithm for FIB-SEM cross-section images, were employed (Figure 1). These methods enabled precise quantification of structural attributes and provided insights into the tunability of supraparticle microstructures for optimized performance. We observed that increasing the spray gas speed during synthesis results in a decrease in the mean size of supraparticles. Additionally, when the spray gas speed is held constant, varying the size of the precursor nanoparticles, produces supraparticles with similar dimensions but distinct microstructural features. SEM images revealed notable variations in morphology and shape, that perfectly aligned with corresponding differences in internal pore structures found by MIP. Specifically, changes in morphology affected the ratio of intra-supraparticle porosity to inter-supraparticle porosity, enabling us to establish a clear correlation between morphological characteristics and pore properties. These findings provide detailed insights into how synthesis parameters influence both the size and internal architecture of supraparticles, offering strategies for fine-tuning their structural attributes to optimize silicon-based anode materials for lithium-ion batteries. References [1] H. Wu, G. Yu, L. Pan, N. Liu, M.T. McDowell, Z. Bao, Y. Cui, Stable Li-ion battery anodes by in-situ polymerization of conducting hydrogel to conformally coat silicon nanoparticles, Nat. Commun. 4 (2013) 1943. https://doi.org/10.1038/ncomms2941. [2] C.K. Chan, H. Peng, G. Liu, K. McIlwrath, X.F. Zhang, R.A. Huggins, Y. Cui, High-performance lithium battery anodes using silicon nanowires, Nat. Nanotechnol. 3 (2008) 31–35. https://doi.org/10.1038/nnano.2007.411. [3] H. Jia, J. Zheng, J. Song, L. Luo, R. Yi, L. Estevez, W. Zhao, R. Patel, X. Li, J.-G. Zhang, A novel approach to synthesize micrometer-sized porous silicon as a high performance anode for lithium-ion batteries, Nano Energy 50 (2018) 589–597. https://doi.org/10.1016/j.nanoen.2018.05.048. [4] S. Wintzheimer, T. Granath, M. Oppmann, T. Kister, T. Thai, T. Kraus, N. Vogel, K. Mandel, Supraparticles: Functionality from Uniform Structural Motifs, ACS Nano 12 (2018) 5093–5120. https://doi.org/10.1021/acsnano.8b00873. [5] A. Amin, M. Loewenich, S.O. Kilian, T. Wassmer, S. Bade, J. Lyubina, H. Wiggers, F. Özcan, D. Segets, One-Step Non-Reactive Spray Drying Approach to Produce Silicon/Carbon Composite-Based Hierarchically Structured Supraparticles for Lithium-Ion Battery Anodes, J. Electrochem. Soc. 170 (2023) 20523. https://doi.org/10.1149/1945-7111/acb66b. Figure 1 Porosimetry ; Mercury intrusion porosimetry ; Materials science ; Intrusion ; Mineralogy ; Spray drying ; Chemical engineering ; Porosity ; Composite material ; Chemistry ; Geology ; Porous medium ; Geochemistry ; Engineering Advanced ceramic materials synthesis ; Silicon Nanostructures and Photoluminescence ; Semiconductor materials and devices