Do you know what the function of lithium-ion capacitor electrolyte is?

Do you know what the function of lithium-ion capacitor electrolyte is?

The progress of human society cannot be separated from the efforts of various industries in society, and the updating and replacement of various electronic products cannot be separated from the efforts of our designers. In fact, many people do not understand the composition of electronic products, such as lithium-ion battery electrolytes.

Lithium capacitor electrolyte is an aspect that cannot be ignored, after all, the electrolyte that accounts for 15% of the capacitor cost also plays a crucial role in the energy density, power density, wide temperature applications, cycle life, safety performance, and other aspects of the battery. Electrolyte is one of the four key materials for lithium-ion batteries, including the positive electrode, negative electrode, separator, and electrolyte. It is known as the "blood" of lithium-ion capacitors and plays a role in conducting electrons between the positive and negative electrodes in the battery, ensuring that lithium-ion batteries obtain high voltage, high specific energy, and other advantages.

Lithium ion capacitors are mainly composed of four parts: positive electrode material, negative electrode material, electrolyte, and separator. Electrolyte is one of the key raw materials for lithium-ion capacitors and the blood of lithium-ion capacitors. Lithium hexafluorophosphate (LIPF6) is the core material of lithium-ion capacitor electrolytes, commonly known as lithium salts, and is the most high-performance and widely used electrolyte.

At present, the pursuit of high specific energy is the research direction of lithium-ion capacitors. Especially with the increasing proportion of mobile devices in people's lives, battery life has become the most critical performance of batteries.

Lithium capacitor electrolyte is the carrier for ion transport in batteries, mainly composed of high-purity organic solvents, electrolyte lithium salts, necessary additives and other raw materials. The electrolyte is generally composed of high-purity organic solvents, electrolyte lithium salts (lithium hexafluorophosphate, LiFL6), necessary additives and other raw materials, prepared in a certain proportion under certain conditions.

The safety of lithium-ion capacitors is important in terms of combustion and even explosion. Firstly, the battery itself is flammable. Therefore, when the battery is overcharged, over discharged, or short circuited, when the battery is punctured and squeezed by the outside world, or when the outside temperature is too high, it may cause safety accidents. Therefore, flame retardants are an important research direction for safe electrolytes.

The selection of electrolytes has a significant impact on the performance of lithium-ion batteries. It must be chemically stable, especially at high potentials and temperatures that are not easily decomposed, have high ion conductivity (>10-3 S/cm), and be inert to the anode and cathode materials and cannot corrode them.

Due to the technical difficulties in recycling lithium-ion capacitors, especially power lithium batteries, improving the lifespan of capacitors is one way to alleviate this situation.

The direct use of metallic lithium as an anode material has a high reversible capacity, with a theoretical capacity of up to 3862mAh · g-1, which is more than ten times that of graphite material, and its price is also relatively low. It is considered the most attractive anode material for the new generation of lithium-ion capacitors, but it will produce dendritic lithium. The use of solid electrolyte as ion conduction can suppress the growth of dendritic lithium, making it possible for metallic lithium to be used as an anode material.