Understanding electrolyte infiltration mechanisms in high-density battery electrodes: A multimodal approach

As the demand for higher battery energy density intensifies, the dimensions of cells and the compaction density of electrodes are on the rise, presenting a formidable challenge in achieving complete electrolyte infiltration into the porous electrode structures. The efficacy of this infiltration process is directly linked to battery performance. Therefore, a nuanced understanding of the underlying scientific principles governing electrolyte infiltration is vital for the design and production of advanced batteries. This study synthesizes real-time potential monitoring, 3D X-ray microscopy computed tomography (XRM-CT) for accurate electrode structure reconstruction, and computational simulations to offer a holistic insight into the infiltration mechanisms. The findings reveal that the electrolyte infiltration progresses through four distinct stages: initial contact, macroporous penetration, microporous immersion, and complete wetting. The uniform distribution of cathode particles and the accompanying widely dispersed, unoriented pores facilitate a gradual and uniform electrolyte immersion. In contrast, the anode's flake-like particles and oriented pores lead to a more rapid infiltration parallel to the electrode plane, resulting in variable changes in conductivity across different electrodes. These observations indicate that the orientation and distribution of particles and pores within the electrodes play a pivotal role in determining their wetting behavior and, consequently, the overall battery performance. This integrative research approach yields critical insights for refining electrode design and enhancing manufacturing efficiency in lithium-ion batteries.