Extensional rheology of battery electrode slurries with water-based binders

[Display omitted] •Extensional rheology of battery electrode slurries is quantified.•Extensional properties are shown to vary signicantly between formulations.•Branched polymer binder dramatically alters slurry behaviour in extension.•Slurry behaviour under extension cannot be predicted from shear.•Extension is a key parameter for understanding and modelling battery manufacturing. Precise rheological properties of inks and slurries are essential to providing homogeneous, well controlled and reproducible coatings, particularly in electrode manufacturing for batteries. The rheology can aid understanding of the slurry structure, as well as optimisation of the process conditions to create electrode coatings with the desired microstructure. The shear rheology is typically measured, however the mixing and coating steps contain significant extensional flows, this omits a significant part of the rheological response. Here the extensional properties of battery electrode slurries are quantified using a miniature extensional rheometer. This requires tiny samples (