Evaluation and screening of Si-based anode materials in commercial Li-ion cells for electric vehicle applications

The commercialization of Si-based anode materials for boosting the energy density of electric vehicle (EV) batteries has been hindered by their several challenges including the volume expansion during the lithiation of Si and the hysteresis behavior during the discharge as compared to graphite anodes. Understanding the electrochemical behavior of Si-based anode materials compared with graphite is very important for their practical use. In this work, we evaluated different types of commercially available Si-based anode materials and compared their first-cycle efficiency and specific capacity with graphite. We also investigated the impact of using different amounts and types of Si-based materials on the voltage profile, hysteresis, capacity of the cathodes, and operating voltage window in Li-ion batteries. Three-electrode cell testing for the cells with Si-based anodes and Ni-rich NCM cathodes was performed to provide an in-depth understanding of charge/discharge voltage profile of anodes and cathodes, respectively. We found that for the commercial use of Si-based anode materials, we need to design the cell by considering not only first-cycle efficiency and specific capacity but also anode swelling, hysteresis behavior introduced due to the Si amount and cell operating window.Graphical abstract