This is a great article on slurry mixing, coating, drying, and calendaring for electrode fabrication.
In this review, the literature associated with slurry characterization, coating, and drying is considered, as these three operations represent a great opportunity for savings in manufacturing time and costs. They also have a significant impact on electrode microstructure, which will ultimately determine the electrochemical viability of the device (seeFig. 2). This analysis is carried out in the sections titled“DesirableSlurry Properties” and“Drying Process Insights.”A brief summary of the influence of the calendering stage is described in“Calendering In-fluence on Morphology.”Novel cathode production methods are being developed in an effort to make more reproducible and favorable morphologies at lower costs. These possibilities are explored in the section titled“Next Generation Electrode Processing.”
In the section of “Conclusion and Outlook”, authors pointed out that, to meet the U.S. DOE cost target for LIBs, continuous cost cutting from electrode manufacturing is mandatory. This lies in reducing inactive components,developing solvent-free processing, and acquiring better understandingof slurry properties, deposition methods, drying mechanisms, and electrode properties. Specifically, the following areas need to be considered:
•Viscosity, the most readily reported and critical rheological feature of a slurry, must be considered in the context of the shear rate, sincea higher LSV can minimize scrap and lead to a more stable coating and a lower HSV makes the coating operation faster and less proneto defects
•The optimal slurry microstructure is dependent on how susceptible the particles are to agglomeration and sedimentation
•Viscoelasticity measurements correlate with the strength of a brid-ging network and are therefore a descriptor of sedimentation re-sistance, though little can be said definitively about the impact ofviscoelasticity on coating
•Rheology can, to a limited extent, be a general indicator of coating homogeneity and therefore electrochemical performance, but empirical evidence suggests that it alone is not a reliable predictor
•Some slurry characteristics, such as appropriate binder concentration, must be informed byfindings from the drying process
•To strike a balance between production speed and microstructure preservation, the drying rate must be varied according to how sensitive the underlying mechanism is to the drying rate
•To realize more cost effective, less hazardous production, it is in the interest of the producer to (1) supplant the toxic solvent NMP with water, (2) minimize the amount of solvent used, or (3) replace wet-coating approaches with dry-coating techniques
•Novel deposition methods are needed for high speed coating
•A scalable procedure to manipulate the pore alignment in electrodes that is applicable to a variety of anode and cathode materials is essential to enhance energy and power density of LIBs
•Tailored electrode architectures are an effective way to boost power density and possibly to enable fast charging, but their effect on cyclelife needs to be verified
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