Investigations on the Effective Electric Loads in Blended Insertion Electrodes for Lithium-Ion Batteries

Blending different types of active materials in one electrode is a great opportunity to improve the overall performance of lithium-ion batteries. Despite considerable progress in the recent years, basic interactions, such as the specific impact of a single component on the blends' properties, are not satisfactorily understood at the moment. In this study, the electric loads of the individual components of a blend are investigated using a special experimental setup in combination with model-like blended electrodes. Systematic studies on the impact of type and mass fraction of the components are conducted for different nominal charge and discharge rates. The experiments reveal that the single components can be charged and discharged independent from each other, according to their characteristic redox activities and the overpotential during operation. This can lead to high effective electric loads (C-rates) subjected to a single component despite a comparatively low total current applied to the electrode. Based on the experimental results, a simple model is developed to estimate maximum effective C-rates of the individual components in an arbitrary blend system. These novel insights are discussed in regarding advantages and disadvantages of battery electrodes with multiple active materials.