What are the basic types of lithium battery electrolyte?

The oxidative decomposition of ordinary lithium battery electrolytes under high voltage limits the development of high-voltage lithium batteries. In order to solve this problem, it is necessary to design and synthesize new high-voltage resistant electrolytes or find suitable electrolyte additives. However, considering economic benefits, the development of appropriate electrolyte additives to stabilize the electrode/electrolyte interface is more favored by researchers. ①New type of carbonate-based high-pressure electrolyte When the traditional carbonate-based electrolyte has a working voltage of more than 4.5V, a violent oxidation and decomposition reaction will occur, causing the lithium battery to be unable to carry out the process of lithium insertion and removal. The new carbonate electrolyte can effectively improve the high-pressure performance of the carbonate electrolyte. ②Nitrile high-pressure electrolyte non-protic aliphatic dinitrile compound NC-(CH)n-CN (nu003d3~8) as an electrolyte has the characteristics of high pressure resistance and safety. When the voltage is 7~8V, it shows good electricity Chemical stability, with high ignition point and flash point. Adding EC or DMC to the nitrile solvent can significantly improve the compatibility of the nitrile electrolyte with the graphite electrode and increase the solubility of the lithium salt. In addition, 1,3,6-hexanetrinitrile has great advantages in the application of high-voltage lithium battery electrolytes due to its better high-temperature storage and cycle performance. However, how to reduce the toxicity and processing cost of nitrile solvents is still an urgent problem to be solved in the application of such electrolytes in batteries. ③The dielectric constant of the sulfone organics in the sulfone high-voltage electrolyte is above 40, and they are in a stable state below 5.5V. For example, sulfolane (SL) is a common solvent with high dielectric constant, wide electrochemical window, and strong polarity. However, sulfone organics have high viscosity, high melting point, and poor compatibility with graphite anode materials. Additives are often added to reduce the viscosity and increase the conductivity of the electrolyte. Therefore, improving the safety performance of sulfone electrolyte and reducing the viscosity of sulfone are still the research directions. ④Ionic liquids High-pressure electrolytes Ionic liquids (ILs) are room temperature molten salts composed of anions and cations, which have the characteristics of high flash point, high ignition point, low volatility, high dielectric constant and wide electrochemical stability window. In the current research, the anion is mostly defined as TFSI-, which is easily reduced to insoluble Li+ compounds at low potentials and forms a passivation film on the surface of lithium and graphite anodes. Pyrrole and piperidine electrolytes have good cycle stability at 2.5 ~ 4.8V, but the conductivity is relatively low, and the resistance is high; imidazole electrolytes have high conductivity, but their cycle stability is poor. Further improvements. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Analysis of the characteristics of the lithium battery separator industry