An Optimization Framework for Enhancing Cycle Life of Composite Positive Electrodes in Lithium-Ion Batteries via Composition Ratio Optimization

Abstract

Lithium-ion batteries still require improvement, and design optimization is an important method that can improve battery performance. This study proposes a novel optimization framework to maximize the cycle life of the positive composite electrode by optimizing the composition ratio of active material (AM), conductive additives, and binder. As the composition of the constituents affects the electrochemical and degradation parameters associated with cell performance and side reactions, the relationship between the AM, conductive additives, and binder material was considered. A fundamental physics-based electrochemical cell model with side reactions was developed to predict the performance and cycle life of a battery. The developed optimization framework was used to maximize battery performances, including volume fraction, capacity, discharge energy (DE), and accumulated discharge energy (ADE). The obtained results verified that the maximum values of the aforementioned features continuously changed with different composition ratios and cycle numbers. Although the maximum difference in capacity or discharge energy changed depending on the sample compositions, the differences between maximum and minimum capacities were up to 22%; this was significant only by changing the composition of the composite electrode. The developed optimization framework can effectively maximize the cycle life and be easily incorporated into real-time applications.