The performance of high-voltage lithium-ion batteries is mainly determined by the structure and properties of active materials and electrolytes. Among them, the matching of electrolyte is also very important. Because with the increase of energy density, the compaction density of positive and negative electrodes is generally relatively large, the wettability of electrolyte becomes poor, and the amount of liquid retention decreases. Low liquid retention results in poor battery cycling and storage performance.

1. Select some solvents with higher oxidation potential and wider electrochemical window (such as sulfones, nitriles and fluorinated solvents).

2. Some positive electrode protection additives can be added to the electrolyte to improve the interfacial properties of the positive electrode material.

3. Add positive electrode film-forming additives into the electrolyte to inhibit the reaction between the electrolyte and the positive electrode material interface.

4. A new type of high-pressure lithium salt is added to the electrolyte as an additive. For example, adding bisoxalatoboric acid (LiBOB) to the electrolyte can also form a film on the surface of the positive electrode material, preventing the side reaction between the electrolyte and the electrode material.

High-pressure additives are generally oxidized preferentially over solvent molecules during the cycle, forming a passivation film on the surface of the positive electrode, stabilizing the electrode/electrolyte interface, and finally realizing the stable existence of the electrolyte under high pressure. It is believed that with the advancement of technology, the use of high-voltage lithium-ion batteries will definitely be the trend in the future.

The electrolyte is very important. The electrolyte is called the blood of the ion battery. On the one hand, the electrolyte is a bridge connecting the positive and negative electrodes. On the other hand, the electrolyte is also a medium for the migration and transfer of ions. , the additive is very critical, some additives can use competitive ions to introduce ions and lithium ions for competitive solvation, thereby changing the solvation structure of the electrolyte.