Oxford imaging technique could improve EV battery charging and life

Researchers at the University of Oxford have developed a novel staining technique that enables visualization of polymer binders in the negative electrodes (anodes) of lithium-ion batteries. These binders, which constitute less than 5% of the electrode by weight, are crucial for maintaining electrode integrity, electrical and ionic conductivity, and mechanical stability but have been difficult to image due to their small quantity and lack of distinct features. By tagging cellulose- and latex-derived binders with traceable silver and bromine markers, the team used X-ray spectroscopy and electron microscopy to reveal the binders' distribution at nanoscale resolution, providing new insights into their behavior during electrode manufacturing. This innovative imaging method allowed the researchers to identify how subtle variations in binder distribution significantly impact battery performance. For example, optimizing slurry mixing and drying protocols reduced internal ionic resistance by up to 40%, addressing a key limitation to fast-charging capabilities. The study also uncovered that thin carboxymethyl cellulose (CMC) binder layers intended as uniform coatings often