Lithium battery electrolyte is introduced and the development present situation

Source: 2020 - 03 - 23 15:03 hits: time is introduced and the development status of lithium battery electrolyte electrolyte is a key data (lithium ion battery 4 big The positive and negative, alienating, electrolyte) Lithium ion batteries are one of the so-called 'blood, the rise of electronic effect between positive and negative pole of the battery, this is to ensure that lithium ion batteries have the advantages of high voltage, the specific proportion can be high. The electrolyte by organic solvent and electrolyte of lithium salts commonly ( Six lithium fluoride phosphate, LiFL6) , the necessary additives such as raw material, under certain conditions, according to a certain proportion. Lithium battery electrolyte is introduced and the development status of organic solvents is a major component of electrolytes, closely related with the function of the electrolyte. Common lithium electrolyte salts are lithium perchlorate, six lithium fluoride phosphate, four fluorine boric acid lithium and so on, but from the aspects such as cost, safety consideration, six fluorine phosphoric acid lithium is the first choice for commercial lithium ion battery electrolyte. The use of additives has not yet been commercialized, but has become one of hot topics in the study of organic electrolyte. Lithium battery electrolyte is introduced and the development status quo of 1. The composition of the electrolyte. 1 organic solvent organic solvents is a major component of the electrolyte, the function of the electrolyte is closely related to the function of the solvent. That is commonly used in lithium ion battery electrolyte solvent ethylene carbonate ( EC) , diethyl carbonate ( 12月) , dimethyl carbonate ( DMC) , carbonic acid ethyl ester ( EMC) And so on, generally do not use the propylene carbonate ( PC) And glycol dimethyl ether ( DME) First, such as solvent for lithium batteries. PC is used for secondary battery, and lithium ion battery graphite cathode compatibility is very poor, in the process of charging and discharging, PC in graphite cathode surface differentiation, combined with the flake graphite layers, resulting in a decline in the circulation function of the battery. However, in the EC and EC + DMC in composite electrolyte can establish a stable SEI. Generally speaking, the EC with a mixed solvent of carbonic acid chain is good electrolyte of lithium ion battery, such as EC + DMC, EC + DEC. For the same electrolyte of lithium salt, such as the LiPF6 or LiC1O4, PC + DME system of mesophase c - of carbon microspheres MCMB data show the charge and discharge with the worst performance ( Related to EC + DEC and EC + DMC system) 。 But it isn't sure whether related additive is added in the lithium ion battery to improve the low temperature performance of the battery. Using organic solvent must strictly control the quality, such as the purity requirements in 99. More than 9%, the moisture content must achieve 10 * 0 6 below. Of solvent purity and stability of organic solvent purity of voltage, there is close relationship between the oxidation potential of the organic solvent is about 5 v, the research of organic solvent oxidation potential of the battery to avoid overcharge, safety is of great significance. Strictly control the moisture in organic solvent has a decisive effect on production of qualified electrolyte. When the moisture content is less than 10 * l0 - 6, can reduce LiPF6 differentiation, reduce the differentiation of SEI, avoid gas expansion. Through the molecular sieve adsorption, atmospheric or vacuum distillation, and introducing the inert gas, its moisture content can be achieved. 1. 2 lithium electrolyte LiPF6 is by far the most commonly used lithium electrolyte, also is the developing direction of the future lithium. Although LiClO4 and LiAsF6 is also used as the electrolyte in the laboratory, the high temperature of batteries function USES LiClO4 is bad, and affect LiClO4 itself is easy to break, this is a strong oxidizer, so it is not suitable for large-scale industrial application of lithium ion battery.