Experimental Study on Solvent Treatment of Lithium Battery Binder PVDF
As an oily binder,Polyvinylidene Fluoride(PVDF)exhibits chemical inertness within the potential range of battery charging and discharging,and does not react with electrolytes or lithium.Therefore,PVDF is usually used as a binder for the positive electrode of lithium batteries.In this experiment,the solvent method is used to treat lithium battery binder,and the organic solvents is taken as carriers to prepare a PVDF solution with a certain concentration gradient,and the viscosity of the solution is measured by a viscometer to analyze the solubility of PVDF in different organic solvents.Among them,there are six types of single component organic solvents,namely N-methyl-2-pyrrolidone,N,N-dimethylformamide,N,N-dimethylacetamide,dimethyl sulfoxide,methyl methacrylate,and tetrahydrofuran;there is one type of two-component organic solvent,which is prepared by mixing N,N-dimethylformamide and N,N-dimethylacetamide(volume ratio 1∶1);there is one type of three component organic solvent,which is prepared by mixing N-methyl-2-pyrrolidone,N,N-dimethylformamide,and N,N-dimethylacetamide(volume ratio 1∶2∶2).The experimental results show that there are differences in the dissolution effect of PVDF by different organic solvents,but the viscosity change pattern of PVDF solutions prepared with most solvents is consistent.As the concentration increases,the viscosity of PVDF solution generally increases exponentially.Compared to single component organic solvents,the improvement effect of viscosity of PVDF solution is not significant when dissolved in multi-component organic solvents.After comprehensive comparison,N,N-dimethylformamide and N,N-dimethylacetamide are selected as the best PVDF solvents for industrial applications.
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