Analyze the five major development trends of lithium battery electrolyte technology

The five major development trends of lithium battery electrolyte technology are analyzed. The electrolyte is an ionic conductor that conducts between the positive and negative electrodes of the battery. It is composed of lithium electrolyte, high-purity organic solvent, necessary additives and other raw materials in a certain proportion. It plays a vital role in the energy density, power density, wide temperature use, cycle life, and safety functions of the battery. Lithium batteries are composed of a shell, a positive electrode, a negative electrode, an electrolyte, and a gap. The electrode data is undoubtedly the focus of attention and research. But at the same time, the electrolyte is also an aspect that cannot be ignored. After all, the electrolyte, which accounts for 15% of the battery cost, does play a vital role in the energy density, power density, wide temperature use, cycle life, and safety functions of the battery. use. The electrolyte is an ionic conductor that conducts between the positive and negative electrodes of the battery. It is composed of lithium electrolyte, high-purity organic solvent, necessary additives and other raw materials in a certain proportion. With the application of lithium batteries in more and more fields, different types of lithium batteries have different requirements for electrolytes. Next, the author analyzes the electrolyte, the key raw material for lithium batteries, on the development trend of the electrolyte. 1. High specific energy electrolytes seeking high specific energy is the biggest research direction of lithium batteries, especially as mobile devices occupy an increasing proportion of people's lives, battery life has become the most critical function of batteries. As shown in the figure, the future development of high-energy-density batteries must be high-voltage anodes and silicon cathodes. -Silicon has a huge gram capacity and people pay attention to it, but because of its expansion effect, it cannot be used. In recent years, the research direction has changed the silicon carbon anode, which has a relatively high gram capacity and small volume changes. , Different films have different additive cycles in the silicon-carbon anode. 2. High-power electrolyte At present, it is difficult for commercial lithium electronic batteries to achieve high discharge rates. The important reason is that the battery is overheated seriously, and the internal resistance causes the overall temperature of the battery to be too high, which is prone to thermal runaway. Therefore, while maintaining high conductivity, electrolyte is needed to prevent the battery from heating up too quickly. Regarding power lithium-ion batteries, completing fast charging is also an important direction for electrolyte development. The high-power battery not only puts forward the requirements of high solid phase dispersion, short ion migration path caused by nanometerization, control electrode thickness and compaction for electrode data, but also puts forward higher requirements for electrolyte: 2. Low solvent complex viscosity; 3. Interface control-reduce membrane impedance. 3. Wide-temperature electrolyte batteries are prone to electrolyte differentiation at high temperatures, and the side reaction between the data and the electrolyte is intensified. However, at low temperatures, the electrolyte salt output and negative SEI membrane impedance may increase exponentially. The wide temperature electrolyte enables the battery to work in a variety of environments. The following figure shows the boiling point comparison and curing comparison of various solvents. 4. The safety of the safety electrolyte battery is mainly reflected in burning or even blasting. The battery itself is flammable, so when the battery is overcharged, overdischarged, short-circuited, when it is subjected to external acupuncture, kneading, and when the external temperature is too high , May cause a safety accident. Therefore, flame retardants are an important direction of safe electrolyte research. Adding flame retardant additives to conventional electrolyte can obtain flame retardant effect. Generally, phosphorus flame retardants or halogen flame retardants are used. The flame retardant additives are required to be reasonably priced and do not affect the function of the electrolyte. In addition, the use of room temperature ionic liquids as electrolytes has also entered the research stage, which will completely eliminate the use of flammable organic solvents in batteries. In addition, ionic liquids have extremely low vapor pressure, good thermal/chemical stability and non-flammability, which will greatly improve the safety of lithium batteries. 5. Long-cycle electrolytes Due to the technical difficulties in the recovery of lithium batteries, especially power lithium-ion batteries, improving battery life is a way to alleviate this situation. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.