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

Abstract

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.

Revisiting Olivine Phosphate and Blend Cathodes in Lithium Ion Batteries for Electric Vehicles

“…Mixing three components at even ratio (33% for each), the ternary blend electrode presents highest electronic conductivity when all the other electrode parameters are controlled at same level (as list in Table 1) [45]. Redox activities studies reveal that each components in blend cathode can work independently and contributes to reduce the over-potential [46]. This is consistent with other reports.…”

Ternary Cathode Blend Electrodes for Environmentally Friendly Lithium‐Ion Batteries

“…applied during charge and discharge are inhomogenously distributed among the different electroactive materials. [14] Supported by simulation studies, the different working potentials result in significantly higher stress of one material at a given potential and the performance of the blend is negatively affected. [15] In contrast to these studies, blend electrodes are generally reported to show advantageous electrochemical performance.…”

“…Liebmann et al. used a model system without intermixed particles to show that the currents applied during charge and discharge are inhomogenously distributed among the different electroactive materials [14] . Supported by simulation studies, the different working potentials result in significantly higher stress of one material at a given potential and the performance of the blend is negatively affected [15] .…”

Porous 3D Architecture of Carbon‐Encapsulated Fe3O4 Nanospheres Anchored on Networks of Carbon Nanotubes as Anodes for Advanced Lithium‐Ion Batteries

“…After the fast charge/discharge for 50 cycles and the current density is restored to 200 mA g −1 , the capacity for the Fe 3 O 4 /CNTs@C composite rise to 776 mA h g −1 . It is notable that the capacity increases after 50 cycles, demonstrating that a thin and stable SEI film formed on the surface of active material improve its activity [13] . On the contrary, the Fe 3 O 4 @C sample cannot recover its capacity to the initial ones when the current density down to 0.2 A g −1 after a 50‐cycle test at 5 A g −1 , which may be due to destruction of the composite without CNTs reinforcing bands.…”

“…In recent decades, many of categories materials, such as oxides and sulfides as well as selenides of metal, have been extensively investigated and explored as anode materials for LIBs [9–15] . Among these materials, Fe 3 O 4 is considered as a favorable candidate material for LIBs owe to its relatively high theoretical capacity of 926 mA h g −1 [16] .…”