The slurry contains active material, conductive agent and binder in solution form, in usual the ratio in weight is 80:10:10 for cathode in research (for anode 90:3:7), but for getting high capacity we need to increase the active material as much as possible. Industries try to optimise the materials for the ratio 93.5:4:2.25. Quality, morphology as well as chemical properties decides the ratio and needs to be optimised for each set of the chemical used. So there is no universal ratio.
There are two methods to make slurry, either binder is mixed along with other solids and then finally solvent or the binder is mixed with solvent to make binder solution and then it is added to the solids containing mixture of active material and conductive agent.
Preparation of PVDF-NMP Solution; the NMP should be minimum and optimized between the porosity (which forms after NMP leaves the coating) and adhesiveness to the foil. For optimization viscosity of the slurry is the best method with adhesion to foil, which can be checked post coating. Solution is prepared beforehand and kept in oven for overnight. In general the ratio of the PVDF:NMP is 1:15
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