Understanding wetting behavior in electrode-electrolyte interface formation and its sensitivity to electrode-current collector interaction: a lattice Boltzmann method approach

The formation of the electrolyte-electrode interface is essential for the performance of Li-ion batteries. This study aims to explore the wetting characteristics of an electrolyte within a porous electrode positioned between a current collector and a separator. By utilizing the Shan-Chen-based lattice Boltzmann method, an in-house code has been developed and thoroughly validated. This code integrates actual contact angles at the interfaces between the electrolyte and battery components. Furthermore, code acceleration through GPU-based parallel programming facilitates adequate meshing, underscoring the novelty and originality of our approach. The results of this study provide insights into the overall saturation curves and imbibition rates and clarify the primary mechanisms of electrolyte wetting within the porous matrix via local wetting rates. The electrode-current collector interface emerged as a critical factor influencing the imbibition rate and gas entrapment tendencies. Pore types at the interface have been categorized, focusing on how the material contact angle variations between the current collector and electrolyte influence wetting dynamics. Notably, it is observed that higher contact angles (90 degrees) between the electrolyte and current collector increase the risk of trapping gas. Conversely, lower angles (15 degrees and 35 degrees) improve overall saturation; however, the enhancement of the wetting rate is particularly noticeable when interconnected pores are present at the interfaces of the electrode and battery components. This study underscores the combined influence of the separator and current collector in comprehending electrolyte wetting behavior, thus contributing to the advancement of battery technology.