The electrolyte in a lithium-ion battery is the carrier of ions. It is generally composed of lithium salts and organic solvents. The electrolyte acts as a conductor of ions between the positive and negative electrodes of a lithium-ion battery, ensuring its advantages such as high voltage and high specific energy. Currently, the most commonly used electrolytes in lithium-ion batteries on the market include lithium perchlorate, lithium fluoride salts, and lithium hexafluorophosphate.
1. Ethylene carbonate: Molecular formula: C3H4O3, transparent colorless liquid (>35℃), crystalline solid at room temperature, is a good solvent for polyacrylonitrile and polyvinyl chloride.
2. Propylene carbonate, colorless and odorless, or pale yellow transparent liquid, soluble in water and carbon tetrachloride, miscible with ether, acetone, benzene, etc. This product should be stored in a cool, ventilated, and dry place, away from fire sources, and transported and stored according to the regulations for general low-toxicity chemicals.
3. Diethyl carbonate, colorless liquid with a slight odor; vapor pressure 1.33 kPa/23.8℃; flash point 25℃ (flammable liquid that can evaporate into vapor and enter the air).
4. Dimethyl carbonate is a non-toxic, environmentally friendly, and widely used chemical raw material; it also has a high evaporation temperature and a fast evaporation rate.
5. Ethyl methyl carbonate, a colorless and transparent liquid, is a high-tech, high-value-added chemical product that has emerged in recent years. It is an excellent solvent for lithium-ion battery electrolytes. This product should be stored in a cool, ventilated, and dry place and transported and stored in accordance with the regulations for flammable chemicals.
6. Lithium hexafluorophosphate, white crystals or powder, highly hygroscopic; decomposes when exposed to air or heated. When exposed to air or heated, lithium hexafluorophosphate decomposes rapidly in the air due to the action of water vapor, releasing PF5 and producing white fumes.
7. Phosphorus pentafluoride is a phosphorus halide compound. At room temperature and pressure, phosphorus pentafluoride is a colorless, foul-smelling gas that is highly irritating to the skin, eyes, and mucous membranes. It is used as a catalyst in polymerization reactions.
The electrolyte in lead-acid batteries is a dilute sulfuric acid solution, prepared by adding concentrated sulfuric acid to water. The quality of the electrolyte greatly affects the battery's lifespan, capacity, and other aspects; therefore, it is essential to master the correct preparation method. The electrolyte for lead-acid batteries must use battery-specific sulfuric acid, and it must be clear, transparent, colorless, and odorless; the levels of iron, arsenic, manganese, chloride, and nitrogen compounds must not exceed the standards.
The electrolyte in lead-acid batteries is a dilute sulfuric acid solution, prepared by adding concentrated sulfuric acid to water. The electrolyte is made by mixing special sulfuric acid and distilled water in a specific ratio, with a density generally between 1.24 and 1.30 grams per cubic centimeter. The specific gravity is 12.75-12.85 g/cm³. If water is consumed during battery use, simply add pure water to recharge the battery.
For example, the electrolyte in lead-acid batteries is prepared by mixing 80% sulfuric acid and distilled water in a certain proportion. Its density is generally 1.24-1.30 g/cm³, and its specific gravity is 12.75-12.85 g/cm³. Some lead-acid batteries (such as motorcycle lead-acid batteries) require the electrolyte to be added manually, so extra care must be taken when adding it to avoid contact with eyes or mouth.
