627-50-9 Purity
0.96
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Specification
Many commercial lithium-ion batteries employ polyvinylidene fluoride (PVDF) as a binder due to its excellent electrochemical stability, wettability with the electrolyte, and acceptable bond strength between the electrode laminate and current collector.
· Preparation of electrode powders: The powder mixtures, composed of 90 wt% LiNi0.33 Co33Mn0.33O2(NMC), 5 wt% conductive carbon black, and 5 wt% PVDF were prepared in a planetary mixer for 4 cycles.
· Effect of PVDF binder: The microstructure and porosity of the PVDF layer depend strongly on the molecular weight of the PVDFs. With increasing molecular weight, the PVDF layer becomes more porous, improving the high-rate capacity without decreasing binding strength and long-term cycling performance of the electrodes.
In order to improve antifouling properties, plasma treatment was used to modify PVDF powder, followed by polymerization to prepare PVDF-g-PAA amphiphilic copolymer, and non-solvent induced phase separation (NIPS) method to prepare modified PVDF membrane.
Preparation of antifouling PVDF membrane
· Evenly distribute the PVDF powder on the cardboard, put it into a plasma chamber, use helium (He, 50 Pa) as the discharge gas, process it at 100 W for 100 s, and then place the treated PVDF powder in the atmosphere for 1 h Fully oxidized.
· Dissolve the treated PVDF powder and dimethylacetamide (DMAC) in a three-flask at room temperature, then add acrylic acid (AA) monomer for subsequent polymerization, and steadily pass nitrogen flow into the mixture for 30 minutes, and then add the three-flask The flask was transferred to an 80°C oil bath and the reaction continued for 1 hour.
· Add PVDF powder to the above mixed solution to obtain a uniform casting liquid. Use a 200 μm pouring knife to pour the pouring solution onto the glass plate and immediately immerse it in the water coagulation bath. All prepared membranes were stored in pure water for 24 h to remove monomers and homopolymers of AA.
In order to improve the dielectric properties of BaTiO3/polyvinylidene fluoride (BT/PVDF) composites such as poor interfacial compatibility and low dielectric constant, a simple modification strategy was adopted to introduce high spontaneous polarization coarse BT particles. In this strategy, the maximum energy density of the obtained BT/PVDF composite is 30×10-3 J/cm3 at 10 kV/mm, which is approximately 4.5 times that of the pure PVDF matrix.
Preparation steps of BT/PVDF composite materials
· First, BT particles of different particle sizes with good dispersion were synthesized through a simple molten salt method by adjusting the calcination temperature.
· PVP-coated BT composites were prepared by modification treatment with water-soluble polyvinylpyrrolidone (PVP) reagent, which exhibited a fine core-shell structure.
· Finally, the powdered PVDF polymer was dissolved in N,N-dimethylformamide (DMF) solvent, and functional PVP/BT nanoparticles were added to the solution with dissolved PVDF. The composite material was obtained after solution sonication, solvent evaporation and hot-pressing processes.