Product Data Sheets

Lithium-ion Battery Binders

Targray supplies a portfolio of Binders materials: Styrene Butadiene Copolymer (SBR) and Polyvinylidene Fluoride (PVDF), used in the cathode and anode electrode slurry making process for Lithium-ion batteries.

Binders such as SBR and PVDF, are used in Lithium-ion batteries to hold the active material particles together and in contact with the current collectors i.e. the Aluminum Foil (Al foil) or the Copper Foil (Cu foil).

A cathode electrode is typically made by mixing active material powder, binder powder, solvent and additives into a slurry (paste) and pumping this slurry to a coating machine. An anode electrode is made similarly by typically mixing Graphite as the active material, together with the binder, solvent and additives into slurry (paste) and pumping this slurry to a coating machine. The coating machines spread the mixed slurry (paste) on both sides of the Al foil for the cathode and Cu foil for the anode. The coated foil is subsequently calendared to make the electrode thickness more uniform, followed by a slitting operation for proper electrode sizing.

With these intricate manufacturing steps, the characteristics of the binder material used are very critical and the material must conform to strict criterion. Some of these characteristics of relevance are:

• Ionic Conductivity
• Tensile Strength
• Water Absorption
• Adhesion Property
• Swelling in Electrolyte
• Melting point and Crystallinity
• Molecular weight distribution
• Dissolution Properties
• Purity

Partnering with global suppliers, Targray offers both SBR and PVDF Binders that are widely used in the Li-ion battery manufacturing industry.

Aqueous base – Modified SBR (Styrene Butadiene Rubber):

In the traditional Li-ion cell manufacturing process, PVDF (Polyvinylidene Fluoride) is mostly adopted in the cathode and anode slurry making processes. For processing requirements, cost and environmental issues, battery manufacturers are gradually moving away from using PVDF and instead making use of aqueous base materials such as SBR copolymers - Modified SBR (Styrene Butadiene Copolymer) Hydrophilic Binder (PSBR-100).

Targray’s Hydrophilic Binder brings new cutting-edge technology to li-ion battery manufacturers. The Modified SBR: PSBR-100 can be used for practically all Li-ion cell chemistries – for both the Anode and Cathode electrodes. This technology offers distinct advantages for Lithium-ion battery manufacturers, including:

• Lower cost of manufacturing.
• ‘Clean’ – pollution-free as compared to use of PVDF that uses NMP solvents.
• Use of water based solvents – environmental friendliness, cleanliness and no pollution.
• Reduction of binder usage amount in the cathode slurry – only about 1.5% for cathode and 4% for anode needed, thus effectively enhancing the overall cell capacity.
• Enhancing the active material ratio in a cell as a result of reduction in SBR amount used – higher energy density is possible.
• No requirement for strict humidity control in the manufacturing process
• Fast drying speed in the electrode fabrication resulting in higher production volumes.

PVDF (Polyvinylidene Fluoride):

PVDF resins are polymers and currently widely used in the Li-ion batteries as binder material , especially in cathodes. PVDF requires NMP (N Methyl 2-pyrrolidone) as a solvent and offers the possibility of high voltage operation. PVDF is also electrochemically stable in contact with electrolyte mixtures. Targray has established a leading supply partner to offer Li-ion battery manufacturers a portfolio of PVDF options.

Polyvinylidene Fluoride (PVDF) resin is the homopolymer of Vinylidene Fluoride. Targray offers a range of PVDF materials with differing properties that allow you to maximize the performance of your particular cell. PVDF powder is a raw material, however, the following are benefits of the PVDF binder :

• Excellent resistance to adverse weather conditions over a wide range of temperatures.
• Excellent mechanical strength
• Outstanding chemical resistance
• Good processing performance and workability

For more product specifications, please view the Product Data Sheets or contact Targray directly. We have the knowledge and capability to help you differentiate which binder is best suited for your manufacturing needs.