The best driver for lithium-ion batteries is electrolytes
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2023/11/16 14:12:20
Lithium-ion batteries use a liquid electrolyte, which allows lithium ions (Li+) to move between the anode and cathode, stabilizing the cathode and anode surfaces, extending battery life and improving battery performance. As one of the four components of the battery, it plays a pivotal role.
The liquid electrolyte acts as a "medium that enables lithium ions to move between the cathode and anode." It can be said that it is the fastest and safest drive in lithium-ion drives.
The liquid electrolyte is composed of lithium salt, organic solvent and additive. They each perform their duties and cooperate with each other to ensure the normal operation of the battery.
Lithium salt - lithium ion channel
The role of lithium salts is to provide channels for lithium ions. The ideal lithium salt should be able to dissolve or dissociate easily in a solvent, so that the dissociated lithium ions can move smoothly. At present, the most widely used lithium salt is LiPF6, which has better ionic mobility, solubility and chemical stability.
Organic solvent - a liquid that dissolves lithium salts
Organic solvents need to have high solubility and low viscosity when dissolving lithium salts to promote the smooth movement of lithium ions.
In order to obtain high ionic conductivity, cyclic carbonates with high solubility and chain carbonates with low viscosity are usually combined. At the same time, the selected solvent also needs to have low chemical reactivity to avoid reactions with water or other substances, so as to ensure the efficient movement of lithium ions.
Additive - The substance that determines the liquid electrolyte
Additives are substances added in small amounts to form a protective film on the surface of the positive and negative electrodes. It helps lithium ions move smoothly between the cathode and anode and prevents battery degradation.
Additives are divided into positive additives and negative additives. Positive additives stabilize the positive structure, protect the surface, and reduce battery aging, overheating, and overcharging. Anode additives form a strong film at the anode, extending service life, preventing overheating and maintaining battery capacity. The positive and negative additives should be dissolved in the liquid electrolyte and chemically stable. Additives make up only a small part, but play an important role in the entire system by extending life, improving high temperature problems and reducing resistance.
It seems hard in theory, but if you compare liquid electrolytes to coffee, you can easily understand. Lithium salt for coffee beans, organic solvent for water, additives for syrup.
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