Investigating the Effect of Various Fluoroethylene Carbonate (FEC) Contents as a Co-Solvent on Cells Containing Advanced Si-C Anode Materials

Producing batteries with higher energy densities has always been a need in various industries, especially EVs. Si-Carbon composites have always been looked at as a promising solution. However, some of the challenges associated with Si as an anode material, such as pulverization, have hindered its widespread adoption in industry. Recent developments have tackled massive volume expansion and pulverization of Si by depositing the Si into highly porous carbons in the form of sub-nanometer Si clusters. 1 Parallel to the development of better Si-containing anodes, there have been numerous efforts on designing electrolytes using various solvents and additives that are compatible with these systems. 2 One of the widely studied additives and co-solvents for Si has been fluoroethylene carbonate (FEC), which is shown to be effective in Si-containing anodes. FEC can decompose on the Si and form a stable solid-electrolyte interphase (SEI), which can tolerate mechanical stress that is induced in the charge and discharge process. 3,4 This study evaluates the effect of various FEC contents (0 to 10 wt%) on the electrochemical performance, such as long-term cycling and open circuit voltage storage of cells containing 20 wt% advanced Si-C composites and 80 wt% artificial graphite in the anode side and Li[Ni 0.83 Mn 0.06 Co 0.11 ]O 2 in the cathode side. References Rathore, D. et al. Characterizing Structure and Electrochemical Properties of Advanced Si/C Anode Materials. J Electrochem Soc 172 , 010504 (2025). Nam, J., Lee, H. & Chae, O. B. Overcoming Challenges in Silicon Anodes: The Role of Electrolyte Additives and Solid-State Electrolytes. Micromachines 2025, Vol. 16, Page 800 16 , 800 (2025). Jung, R. et al. Consumption of Fluoroethylene Carbonate (FEC) on Si-C Composite Electrodes for Li-Ion Batteries. J Electrochem Soc 163 , A1705–A1716 (2016). Ha, Y. et al. Evaluating the Effect of Electrolyte Additive Functionalities on NMC622/Si Cell Performance. J Electrochem Soc 169 , 070515 (2022).