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Slot die coating window for a uniform fuel cell ink dispersion |
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| Authors: | Weitong Pan Zhekun Chen Xueli Chen Fuchen Wang Gance Dai |
| Affiliation: | 1. Institute of Clean Coal Technology, East China University of Science and Technology, Shanghai, China;2. Institute of Clean Coal Technology, East China University of Science and Technology, Shanghai, China
Contribution: ?Investigation (supporting), Resources (lead), Writing - review & editing (supporting);3. State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, China |
| Abstract: | The continuous roll-to-roll slot die coating technique has shown great potential for fuel cell electrode fabrication. It is essential to determine the particulate coating window to obtain a defect-free film of uniform thickness and uniform particle dispersion. For this dual-purpose, an additional upper operating limit has been proposed via a “flow field analysis scheme” that combines analysis and simulation. In this analysis, the fundamentals of flow pattern transition (Poiseuille–Couette–bubbly flow) behind coating limits are clarified. The Couette flow is advantageous for uniform shear rate and dispersion. Furthermore, phase-field simulations systematically investigate the effect of fluid and geometrical parameters and quantitatively present the flow limit with explicit expression. Results reveal that the slope of the upper limit is inversely correlated with shear-thinning index n while proportional to the coating gap H. Combining the bubble entrainment boundary, lower n and H are favorable for a larger particulate coating window. |
| Keywords: | coating gap particulate coating window phase-field method shear-induced migration shear-thinning |