Polyvinylidene fluoride (PVDF) as anode and cathode binder for lithium batteries
-
Polyvinylidene fluoride (PVDF) is a kind of polymer material, which has good chemical stability and machinability, and plays a positive role in improving the bonding performance. It is widely used in lithium-ion batteries as a positive and negative binder.
The main factors affecting the adhesion of PVDF are molecular weight, crystallinity, PVDF modification, cathode material and conductive agent. The larger the molecular weight of PVDF is, the stronger the adhesion is, and the higher the peeling strength of the electrode is. The higher the crystallinity is, the closer the molecular chains are, the greater the intermolecular force is, and the better the adhesion is.
The solubility of PVDF in solvent is mainly affected by crystallinity, particle size, molecular weight, polarity and dissolution temperature. In addition to the dissolution of PVDF powder, the water content of NMP solvent should be specially controlled. The water absorption degree of NMP is more serious than that of positive active material, conductive agent and other materials. It is easy to attack the pH value of the adjacent molecules of nmc-h and dfc-h in the slurry. The increase of the number of double bonds will cause the viscosity of the slurry to increase. When it is serious, it will produce gel like jelly, which can not be properly coated.Physical Typical Value（Unit） Density 1.75 to 1.78g/cm3 Water Absorption (30g，73°F, 24 hr) ＜0.20% Volatile content <0.20% Molecular weight 1000000-12000000 Particle size D50 70 – 140μm Tensile Modulus (73°F， 0.039 in/min） 145000 to 218000 psi Glass Transition Temperature (DSC) -40.0℉ Melting Temperature 160-168°C Peak Crystallization Temperature (DSC) 135-140°C Heat of Fusion 3（80°C to end of melting） 40.0-48.0J/g Surface Resistivity （Voltage < 1V, after 2 min - 500 V @ 23°C） ＞1.0E+14 ohm Volume Resistivity （ Intensity = 10 mA, after 2 min @ 23°C） ＞1.0E+14 ohm·cm Intrinsic Viscosity 0.27-0.31l/g Package 20kg/PC Chemically modified high molecular weight PVDF is used in LCO, LFP (nano) and NMC / NCA batteries with the following characteristics:
1. High cohesion between active substances
2. Excellent adhesion with collector
3. It has good chemical properties at high temperature
4. Anticoagulant gelling of high nickel positive electrodeChemically modified PVDF5130 for improved stability with Ni-rich AM
Excellent Chemical resistance
Better Cycleability
Excellent Adhesion
AFT-PVDF5130 gives access to important improvements:
Improved adhesion with many different active materials
Possibility to reduce binder content to achieve higher energy density
Delivery Time:In Stock
