New electrolyte additive LiTDI improves battery life and charging speed

In the electric vehicle market, with the surge in demand for lithium-ion batteries, researchers are stepping up the development of new electrolytes. The new electrolyte not only needs to ensure the performance, life and safety of the battery, but also meets the requirements of high-energy anode materials (such as silicon) and cathode materials (NMC 811, etc.). High-purity electrolyte can reduce battery side reactions and avoid premature battery degradation, which is of great significance.

According to foreign media reports, Arkema's new electrolyte additive LiTDI can not only extend battery life and speed up charging, but also solve the problem of material purity and stability for the high-capacity battery materials necessary for electric vehicles.

LiTDI, lithium 4,5-dicyano-2- (trifluoromethyl) isopyrazole, originally discovered by Warsaw University of Technology (WUT), Warsaw University of Technology, French National Center for Scientific Research (CRNS) and French University of Amiens (University of Amiens) Cooperative research on its synthesis and purification. When Dr. Gregory Schmidt was in the team of Professor Michel Armand of the University of Amiens, France, he tried to apply this lithium salt to lithium-ion batteries, and focused on the synthesis and electrolyte formulation. Research results show that additives made with this lithium salt can greatly improve electrolyte performance. The researchers integrated this molecule into Arkema ’s powerful battery platform and renewable energy solutions.

LiTDI has many advantages, and its molecular structure has been tailored to greatly improve electrochemical stability and promote ion dissociation. The isopyrazole ring promotes the dissociation of negative charges through the resonance effect. Secondly, the electronegativity / weight ratio of the two nitrile groups is optimized, which can further promote the dissociation of positive charges. Finally, the F3 group attached to the isopyrazole ring is beneficial for maintaining electrochemical stability. Cyclic voltammetry studies have shown that the molecule has no reactivity below 4.6 ~ 4.7V. In addition, DSC research shows that these molecules have extremely high thermal stability, and they will only degrade when the temperature is higher than 250 ℃. It is the best choice for lithium-ion batteries that work under high pressure and high temperature for a long time.

In the electrolyte, in addition to its inherent stability, LiTDI is also an important dehumidifier. Lithium ions and carbonitrile groups interact with water molecules to trap water molecules through hydrogen bonding, thereby effectively inhibiting the hydrolysis of LiPF5. LiPF5 is a decomposition product of LiPF6 on the negative electrode, is a strong Lewis acid, and is the main cause of electrolyte solvent degradation. In addition, due to the degradation of LiPF6, the nitrile group interacts with the HF molecule, which can further reduce the parasitic reaction on the positive side. By reducing the influence of impurities on different electrolyte components, only 1% of LiTDI can be added to improve electrolyte stability and extend battery life.

In addition, LiTDI helps to form a passivation layer on the aluminum current collector and can also have an important impact on battery performance. Researchers have tried to find LiPF6 alternatives suitable for high-voltage applications, but the corrosion phenomenon that occurs on the positive electrode current collector can increase the internal resistivity and reduce the positive electrode capacity. For batteries containing new electrolytes based on alternative salts (LiFSI, etc.), a stable aluminum protective layer formed from LiTDI helps increase battery life and supports the use of high-voltage electrodes (such as NMC 622).

It is worth mentioning that LiTDI helps to form a stable solid electrolyte interface film (SEI) and protect the negative electrode from degradation reactions of organic solvents. LiTDI is combined with traditional SEI additives (such as FEC or VC) to help the growth of LiF mineral phases and promote the formation of polymer phases by defluorinating CF3 groups. The resulting SEI film is thinner and has strong cross-linking, which helps reduce resistivity and reduce initial capacity loss. This phenomenon occurs not only on the graphite negative electrode, but also on the silicon-based positive electrode. For battery life and battery internal resistance, SEI additives can play a more important role.

To sum up, in Li-ion batteries, LiTDI additives and traditional SEI additives work synergistically, the battery impedance is reduced, and the rapid charge and discharge performance is significantly improved. In addition, this salt can improve electrolyte purity and stability, enabling traditional electrolytes to cycle at high temperatures (> 45 ° C). Finally, LiTDI is a very good electrolyte additive, whether it uses graphite anodes or silicon-based cathodes, it can significantly extend battery life. (Author: Elisha)

Hex Nut

Brass knurled thread insert Made of material, good thermal conductivity and heat resistance.

Widely Used On the Injection molding for Tightly Fixing.

Can be installed by ultrasonic or heat into thread tapered hole, or molded in during injection.

China leading manufacturers and suppliers of Hex Nut,Hexagonal Nut, and we are specialize in Stainless Steel Nuts,Hex Nut Bolt, etc.

Brass hex nut,hex coupling nut,hex flange nut,hex thin nut,hex bolts and nut

Shenzhen Lanejoy Technology Co.,LTD , https://www.grill-grid.com