Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Design and Optimization of SiO-Graphite Composite Electrodes for Fast Charging of Lithium-Ion Batteries: A Modeling and Experimental Investigation

Silicon monoxide (SiO) blended with graphite is emerging as a highly promising anode material for next-generation lithium-ion batteries, primarily because of its higher energy density compared to conventional options. Unlike single-material electrodes, composite anodes combine heterogeneous materials with different particle sizes, leading to complex, nonlinear electrochemical interactions. Understanding these dynamics requires computational modeling, which offers deeper insights into intercalation behavior and performance. In this study, we investigate a SiO-graphite composite electrode to improve discharge capacity under high C-rate conditions. Using COMSOL Multiphysics 6.1, we modeled the effects of SiO content, particle size, and charge/discharge rates on electrode performance. The results show that higher SiO content improves rate capability. At lower C-rates, the state of charge (SOC) across particles remained relatively uniform. However, at higher C-rates, significant variation in SOC was observed between graphite and SiO particles of different sizes. To address this, we propose an optimized design that narrows the SOC gap between SiO and graphite. With 30.27 wt.% SiO at a 2C lithiation rate, the half-cell achieved 434 mAh g⁻¹, with graphite and SiO reaching SOC values of 0.58 and 0.67, respectively. In comparison, the experimental and simulated results aligned closely, showing only a 9% deviation in discharge capacity. This work provides broader insights into designing fast-charging, composite based electrodes and shows a practical modeling approach that can be extended to commercial-grade cell development.