LUNA ACE - Dispersant for lithium-ion batteries | Resource energy and Batteries

Lithium-ion batteries are widely used throughout the world as batteries for smartphones, electric vehicles, renewable energy power generation equipment, etc. With demand expected to increase in the future as we work to protect the global environment and realize a decarbonized society, the challenge now is to increase battery capacity, enhance productivity and reduce environmental load during the production process.
LUNA ACE, a dispersant developed by Kao for lithium-ion batteries selectively disperses the conductive material which helps increase battery capacity, enhance productivity and reduce environmental load.

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Structure of lithium-ion batteries
and the function of dispersants

Features of
LUNA ACE

Solutions

Battery evaluation
in Kao

Structure of lithium-ion batteries and the function of dispersants

Lithium-ion batteries are comprised of a positive electrode (cathode), a negative electrode (anode), a separator that divides the two electrodes and an electrolyte that fills the gap in between. The electrodes consist of a metal foil, an active material containing lithium, a binder which helps to adhere the active material to the foil, and a conductive material (carbon black or CNT*, etc.) which plays the role of conducting electricity.

Carbon black and CNT used in conductive materials have a very large specific surface area and are difficult to disperse, therefore a superior dispersant is required to form an optimal conductive network.
On the other hand, the dispersant itself is an impurity in finished lithium-ion batteries, making it extremely important to suppress the adverse effect it has on battery performance.

*CNT = Carbon nanotubes

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Features of LUNA ACE

Harnessing its unique polymer design technologies cultivated for dispersing a variety of fine particles such as pigments for inkjet, metals for electronic materials, etc., Kao has developed a highly functional dispersant suitable for lithium-ion batteries.
LUNA ACE has the following three functional groups.

● Adsorbent group: Enables selective adsorption to conductive material
● Dispersant group: Achieves superior dispersion
● Functional group: Suppresses dissolution into electrolyte, providing high voltage endurance

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LUNA ACE dramatically reduces the viscosity of the electrode paste.

Superior dispersion provides the following benefits.

● Increases the solid content of electrode paste and reduction in the amount of solvent used
● Reduced viscosity of electrode paste for materials that are difficult to disperse, such as CNT
● Enhanced electrode yield (formation of smooth coating)
● Enhanced productivity
● Reduced environmental load

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Benefits of low viscosity electrode (cathode) paste
using LUNA ACE

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Comparison of electrode (cathode) paste
(solid content : 75%)

Solutions

Enhance battery productivity

Reduce battery production costs

Superior dispersion helps reduce the amount of solvent used

Due to its superior dispersion, the dispersant developed by Kao helps drastically reduce the increase in viscosity caused by conductive material. By increasing the solid content, the amount of solvent used can be reduced, which helps reduce energy required for drying and VOCs.

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Avoid adverse effect caused by dispersant

Molecular design to prevent dissolution in electrolytes

Commercially available dispersants dissolve in electrolytes and would inhibit the movement of lithium ions and cause electrical reactions. Kao's dispersant has a molecular design to prevent dissolution in electrolytes, minimizing the adverse effect on battery performance.

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Enhance battery performance

Higher capacity achieved by lowering electrical resistance

Superior dispersion enables the formation of an ideal conductive network, enabling higher capacity and improved cycle durability. Enhanced durability also means enhanced safety.

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Battery evaluation in Kao

Kao has established a framework for the evaluation of its batteries, and after confirmation of battery performance using Kao's dispersant, we are able to provide optimum formulations to achieve superior performance.

[Test items]
● Coin cell/laminated cell battery production
● CV measurement
● Charge/discharge measurement
● Cycle evaluation
● AC impedance
● Environmental test

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