Fast ion conductor

Electrical engineering

Physics

Nanotechnology

Electrode

Porosity

Composite number

Ionic conductivity

Engineering

Conductivity

Physical chemistry

Composite material

Power (physics)

Tortuosity

Chemistry

Materials science

Cathode

Battery (electricity)

Electrolyte

Electrochemistry

Limiting current

Microstructure

Thermodynamics

ACS Applied Materials & Interfaces

In the pursuit for future mobility, solid-state batteries open a wide field of promising battery concepts with a variety of advantages, ranging from energy density to power capability. However, trade-offs need to be addressed, especially for large-scale, cost-effective processing, which implies the use of a polymeric binder in the composite electrodes. Here, we investigate three-dimensional microstructure models of the active material, solid electrolyte, and binder to link cathode design and binder content with electrode performance. Focusing on lithium-ion transport, we evaluate the effective ionic conductivity and tortuosity in a flux-based simulation. Therein, we address the influence of electrode composition and active material particle size as well as the process-controlled design parameters of the void space and binder content. Even though added in small amounts, the latter has a strong negative influence on the ion transport paths and the active surface area. The simulation of ion transport within four-phase composites is supplemented by an estimation of the limiting current densities, illustrating that application-driven cell design starts at the microstructure level.

Modeling Effective Ionic Conductivity and Binder Influence in Composite Cathodes for All-Solid-State Batteries