Introduction
At the University of Birmingham within the School of Metallurgy and Materials, researchers are studying the full lifecycle of battery materials - from raw material sourcing and selection, through manufacturing and performance, to end-of-life recycling. Within this cycle, manufacturing research plays a crucial role. One of the most persistent challenges lies in ensuring high-quality slurry mixtures, which are essential for effective electrode coating and consistent battery performance. The difficulty stems from the highly opaque nature of these slurries, which makes agglomerate size measurement particularly difficult using conventional techniques.
Historically, the team have relied on the manual Hegman gauge test to assess slurry quality. However, this method was hampered by poor reproducibility and subjective interpretation of results. Because the slurries are opaque, results varied greatly between users. Meaningful data extraction was limited to visual breakthrough points – a sub-standard metric for research-grade quality control.
The group sought a probe of agglomerate size to support their manufacturing research. TIDAS is the only tool on the market they could find which can take reproducible readings from completely opaque samples owing to dark field illumination techniques and now the system bolsters the team’s suite of slurry characterisation metrology.
Saving time and money
The TIDAS system gives researchers an early indication of whether a slurry is suitable for coating and well dispersed to prevent issues later on, such as limited cell capacity. The time and material savings have been significant since it’s implementation. If a slurry that is un-coatable (the particle size it too large for calendaring) is detected early, this saves around 1 hour in wasted coating trials. The significant benefit however comes from early identification of poorly dispersed slurries (the particles are in not well mixed or have agglomerates).
Beyond time savings, the lab also benefits from reduced material waste - avoiding unnecessary use of foils, cell casings, and electrolytes - and freeing up equipment and researcher time by avoiding repeat experiments.
Real-world impact
The TIDAS has proven especially useful in a range of ongoing research areas. In trials exploring the use of water-based biopolymer binders in electrode formulations, the system provides a crucial first check on slurry consistency before full testing begins. It has also enabled the team to confidently work on 3D-printed electrode coatings, where slurry agglomerate size must be smaller than the nozzle opening to prevent blockages. Additionally, TIDAS has bolstered the group’s contribution to the Faraday Institution’s NEXTRODE project, supporting new metrology for advanced electrode manufacturing.
Looking ahead, the research team sees huge potential for this technique in industry. The ability to measure and trace slurry quality early in the production process could reduce waste during the setup of commercial coating lines and help manufacturers adopt new technologies more easily by catching dispersion issues before they escalate.