Science and Technology Daily, Beijing, July 25 (Reporter Chang Lijun) In order to prevent battery leakage and short circuit, usually a layer of porous film is applied between the battery poles for isolation. Recently, researchers from Ulsan National Institute of Science and Technology in South Korea designed a cellulose nano-mat (c-mat) insulation film. A thin layer of porous cellulose was added to a layer of thicker macroporous polymer, which effectively solved the problem. It is difficult for the traditional electrode separation film to take into account the contradiction between leakage prevention and efficient ion transmission.

 

Researchers recently published a paper in the "Nano Express" claiming that the new c-mat insulation film developed by them is a thin functional nanofiber on the upper layer and a thicker polymer on the lower layer. By fine-tuning the thickness of the two layers, a fine balance is achieved between leakage prevention and supporting fast ion transmission: the tiny nanopores in the cellulose layer prevent current leakage between the electrodes; the larger channels in the polymer layer support the ion "high-speed path" The charge is transferred quickly. It also has an important advantage. At a high temperature of 60 ° C, a battery using a c-mat membrane retains 80% of its power after 100 cycles, while a battery with a conventional polymer barrier layer at the same temperature has only 5% of its power left. .

 

The researchers explained that lithium salts and water in commercial batteries will react side by side, generating harmful by-products such as manganese ions, which will cause great loss of power at high temperatures. The nanoporous cellulose on the c-mat membrane can chelate with manganese ions, preventing them from participating in the reaction, and the macroporous polymer layer can also capture acidic reactants that produce manganese ions, so there are fewer manganese ions at the beginning.

 

Co-author of the thesis and professor of the School of Energy and Chemistry, Li Shanyang said that their research proved that the active cellulose c-mat insulation layer can reduce the side effects of manganese ions and improve the cycling performance of the battery at high temperatures. The effect exceeds the current state-of-the-art Traditional isolation membrane technology.

 

In the next step, they plan to transform the isolation layer so that it can be used in next-generation rechargeable batteries such as sodium-ion batteries, lithium-sulfur batteries, and metal-ion batteries. Li Shanyang predicts that the next-generation high-performance battery using c-mat as an isolation film has good high-temperature stability. It can be used not only in electric vehicle batteries and power grid storage systems, but also in seawater desalination and heavy metal ion monitoring.

 

Chief Editor Circle

 

In order to prevent battery leakage and short circuit and balance battery efficiency, Korean scientists have been trying to develop more efficient battery isolation films. In fact, they have already produced lithium-ion battery separators as early as 2012. At that time, cellulose was also used to have excellent conductivity, electrical and chemical safety, and can be used in a variety of electrolytes. Create high-quality lithium-ion batteries. This time, South Korean scientists are working hard again to use an active cellulose c-mat insulation layer with fewer side effects on manganese ions, which further improves the cycle performance of the battery at high temperatures, and adds new tiles to the new high-efficiency battery.

 

(Responsible editor: Robert)

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