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Lithium battery performance technology has improved, please listen to HOPPT BATTERY analysis for you.

July 8, 2020

Lithium battery performance technology has improved, please listen to HOPPT BATTERY analysis for you.

 

Silicon anodes have attracted considerable attention in the battery industry.


They provide three to five times the capacity of lithium-ion batteries that use graphite anodes.


Higher capacity means batteries will last longer after each charge, significantly extending the range of an electric car.


Although silicon is abundant and cheap, the charging and discharging cycle of Si anodes is limited.


During each charge and discharge cycle, their volume will significantly increase, and even their capacitance will decrease, which will lead to the fracture of the electrode particles or the lamination of the electrode film.

 

On 20 July, a team at the Korea Institute of Science and Technology, led by Professor Zhang Yu-Cai and Professor Ali Coskun, reported a molecular pulley binder for high-capacity lithium-ion batteries with silicon anodes.

 

The KAIST team integrated molecular pulleys, called polyurethanes, into the battery electrode binder, including adding polymers to the battery electrode to attach the wire to a metal substrate.


The rings in the polyurethanes are screwed into the polymer skeleton and can move freely along the frame.

 

The rings in polyurethanes are free to move with the volume of the silicon particles.


The slip of the ring effectively preserves the shape of the silicon particles to not disintegrate during continuous volume changes.


It is worth noting that even broken silicon particles can remain agglomerated due to the high elasticity of polypentane adhesives.


The new adhesives' functionality contrasts sharply with the functionality of existing adhesives, which are often simple linear polymers.


Existing adhesives have limited elasticity and therefore do not hold the particle shape firmly.


Previous adhesives spread the broken particles, reducing or even losing the capacity of the silicon electrodes.

 

According to the authors, this is a good demonstration of the importance of basic research.


Polyrotanes won last year's Nobel Prize for the concept of "mechanical bonds."


"Mechanical bonds" is a newly defined concept added to classical chemical bonds, such as covalent, ionic, coordination, and metallic.


Long-term basic research is addressing the long-term challenges of battery technology with surprising speed.


The authors also note that they are currently working with a large battery manufacturer to integrate their molecular pulleys into actual battery products.

 

Sir Fraser Stoddart, who won the 2006 Nobel Prize in Chemistry at Northwestern University, added: "Mechanical bonds have restored for the first time in an energy-storing environment.


Poly KAIST team skillfully in the slip ring rotaxanes and functionalization of alpha-cyclodextrin spiral polyethylene is used in the machinery adhesive when using glue roller to form micelles; ethylene glycol is the market breakthrough, the performance of lithium-ion battery compounds in only one kind of chemical bonds instead of traditional materials, this will have a significant impact on the performance of the materials and equipment.