Correlating Processing Conditions to Short- and Long-Range Order in Coating and Drying Lithium-Ion Batteries

Abstract

Processing conditions of battery slurries into electrodes are known to affect final battery performance. However, there is a lack of fundamental understanding of how the relationships between processing conditions, the slurry microstructure, and the film microstructure affect electrode performance. This study determines the effects of the coating shear rate and drying temperature on battery electrode performance via discharge capacity. We use rheological measurements and energy dispersive X-ray spectroscopy (EDS) to correlate slurry and electrode microstructures to trends in discharge capacity. The radial distribution function is used to quantify differences in the electrode microstructure. More specifically, we show that the correlation between carbon and active material EDS detections to be the most relevant in understanding battery performance. Electrodes with both short-and long-range carbon/active material orders have the highest discharge capacities. This microstructure can be obtained through high shear rates, which induce better carbon dispersion via strong hydrodynamic forces, or through high temperature drying by preventing unwanted time-dependent structural changes after flow cessation. This analysis provides concrete evidence for the importance of both short-range and long-range contacts between the conductive additive and active material on battery performance.

Reduced Drying Time of Anodes for Lithium‐Ion Batteries through Simultaneous Multilayer Coating

“…A different electrode structure of the multilayer films compared with the single layers due to the increased shear rate of the thinner coatings, as was reported by Saraka et al, can therefore not be entirely excluded. [20] This influence should be minimal though, based on measurements of the dynamic viscosity in the relevant range for coating (see Figure S2, Supporting Information).…”

“…[19] It was also reported that processing conditions like shear force during electrode coating and temperature during drying influence cell performance. [20] In summary, the local state of the material on the molecular level influences bonding mechanisms and thus electrode properties. This influence does not only evolve from the actual material specifications but also from their impact on the subsequent processing steps.…”

Understanding the effect of coating-drying operating variables on electrode physical and electrochemical properties of lithium-ion batteries

“…Drying temperature on binder distribution was researched by Müller et al [25] and Jaiser et al [26] on graphite anodes, revealing that low drying rates improve battery rate capability and cell capacity. Saraka et al [27] studied the effect of coating and drying through analysing shear rate and drying temperature of NMC111 electrodes at laboratory scale. Other works have focused on understanding the effects of mixing sequence or mixing intensity on intermediate product properties or final electrochemical performance [28][29][30].…”

Semitransparent Printable Mesoscopic Perovskite Solar Cells for Tandem Solar Cells

“…[ 17 ] The electron transport of an mesoporous of an electrode is directly related to the structure and connectivity between components. [ 18 ] Microstructure and connectivity of the porous electrode, in turn, strongly depend on the property of ITO conductive oxides, the performance of the paste, and the postannealing process. To further investigate the role of annealing temperature, ITO particle size, and dispersant, Hall migration analyzer was employed to record its electrical conductivity.…”