Requirements and applications of lithium ion -Lithium - Ion Battery Equipment

Requirements and applications of lithium ion battery electrolyte -Lithium - Ion Battery Equipment

Requirements and application of lithium ion battery electrolyte. At present, solid-state lithium-ion batteries can be divided into inorganic solid-state electrolyte batteries and polymer solid-state lithium-ion batteries. The performance of electrolyte has a crucial impact on the performance of the whole battery. It has a very important impact on the battery cycle performance, operating temperature range and battery durability. For lithium-ion batteries, the composition of electrolyte involves at least two aspects: solvent and lithium salt.

Application of lithium ion battery electrolyte

Electrolyte is one of the core materials that make up the capacity of lithium secondary battery and lithium primary battery, which constitute the energy of mobile phones, notebooks, video recorders and other portable machines. It also improves the mobility between mobile anode and cathode and plays a role as a medium. As an important part of lithium-ion battery, electrolyte plays the role of transporting ion conduction current between the positive and negative electrodes. Choosing appropriate electrolyte is also the key to obtain lithium-ion secondary battery with high energy density and power density, long cycle life and good safety performance.(Lithium - Ion Battery Equipment)

The electrolyte of lithium-ion battery is the mutual use between electrolyte and electrode material in the battery. It has decomposition reaction itself, and participates in almost all the reaction processes occurring inside the battery. At present, the electrolyte contained in lithium-ion batteries is mostly organic system. Under the abuse of overcharge, over-discharge, short circuit and thermal shock, the battery temperature rises rapidly, and the electrolyte is generally flammable, which often causes the battery to fire or even explode.

Electrolyte is an important part of lithium-ion battery. It is used to transport ions and conduct current between the positive and negative poles. From the phase state, lithium ion battery electrolytes can be divided into liquid, solid and molten salt electrolytes.

Electrolyte requirements for lithium ion batteries

● Lithium ion conductivity: the electrolyte does not have electronic conductivity, but must have good ionic conductivity. The conductivity of the electrolyte is within 1 in the general temperature range × 10-3~2 × 10-3S/cm. As an electrolyte, it must have excellent ionic conductivity and electronic insulation, so that it can play the role of ionic transmission medium and reduce its self-discharge.

● Ion migration number: the internal transport charge of lithium-ion battery depends on the migration of ions. High ion migration number can reduce the concentration polarization during electrode reaction, resulting in high energy density and power density of the battery. The ideal lithium ion migration number should be as close as possible to 1.

● Stability: When the electrolyte is in direct contact with the electrode, side reactions should be prevented as much as possible, which requires the electrolyte to have certain chemical stability and thermal stability.

● Mechanical strength: lithium ion battery electrolyte shall have enough mechanical strength to meet the large-scale production and packaging process of battery. Li et al. used trimethyl phosphate (TMP) as the additive of the high voltage electrolyte and Li1.2Mn0.54Ni0.13Co0.13O2 as the positive electrode of the battery. The results showed that adding 1% TMP in the electrolyte could significantly improve the rate performance and cycle performance of the battery.

● Excellent mechanical properties: due to the direct contact with the positive and negative electrodes, the polymer lithium ion battery electrolyte should have strong toughness, and can withstand the change of stress during the battery assembly, storage and use, without brittle cracking. At the same time, as a diaphragm, it should also have considerable mechanical strength to inhibit the occurrence and puncture of lithium dendrites and prevent the short circuit of positive and negative electrodes.

In general, in the application field of power lithium-ion batteries, the current mainstream liquid electrolyte and gelled electrolyte have certain potential safety hazards. Therefore, the development of anti short circuit, anti overcharge, anti thermal runaway, anti combustion and non combustible electrolyte is the key to deal with the safety of power lithium-ion batteries.



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