Investigating the Impact of Si/C Supraparticles Size Distribution on the Lifetime of Li-Ion Battery Half-Cells

Abstract

The development of high-performance anodes for lithium-ion batteries (LiBs) with robust cycling stability has become a prominent area of research. In our recent study (Amin et al. 2023), we demonstrated that adopting a hierarchical structuring strategy via spray drying can significantly improve the cycle life of silicon-based anode materials in contrast to their nanoparticle building blocks (4 wt.% of compounding carbon). This method enhances the structural stability of the anode, thereby improving cyclic performance and paving the way for the development of high-capacity LIBs.However, beyond phenomenological proof of principles, understanding the effect of supraparticles size distribution on electrochemical performance is of great significance for making Si-based active materials ready for the LiBs industry. Therefore, we systematically investigated the correlations between supraparticle median sizes/size distributions and other supraparticle properties such as their BET surface area, slurry rheology, coated layer quality, and the electrochemical Coulombic efficiency of half-cells. These findings revealed that supraparticles with large median sizes are stable against processing as compared to small size supraparticles as can be seen from atomic force microscopic (AFM) images of coated layers in Fig 1a. It is also discovered that large supraparticles enhance the 3rd cycle Coulombic efficiency (2 formation cycles) of Li-ion half cells at 0.5 C as shown in Fig.1b. However, there exists an optimal median size/size distribution above which the Coulombic efficiency and cycling stability of the supraparticles in half-cells starts to decrease.In short, supraparticles exhibit properties (e.g., high layer stability, low surface reactions) that outperform those of individual nanoparticles. Understanding the role of supraparticle sizes in generating anodes with a hierarchical structure demonstrates great promises towards tailored materials for enhanced LiB performance. This enables us to further unravel process-structure-property relationships and understand the physics behind the improved electrochemical performance of supraparticles. Publication bibliography Amin, Adil; Loewenich, Moritz; Kilian, Stefan O.; Wassmer, Theresa; Bade, Stefan; Lyubina, Julia et al. (2023): One-Step Non-Reactive Spray Drying Approach to Produce Silicon/Carbon Composite-Based Hierarchically Structured Supraparticles for Lithium-Ion Battery Anodes. In J. Electrochem. Soc. DOI: 10.1149/1945-7111/acb66b. Figure 1