The effect of several common electrolyte additives for lithium ion batteries
Electrolyte additives have an important impact on the safety and life of lithium batteries, and are indispensable components of lithium batteries. The common electrolyte additives include cyclic carbonate, organic sulfates and sulfonates, and lithium salts. This paper will introduce the functions of these common electrolyte additives for lithium batteries. Cyclic carbonates, including FEC 114435-02-8 and VC 872-36-6, have good properties of SEI film, which can form a compact structure layer without increasing impedance, which can effectively prevent further decomposition of electrolyte and improve the low-temperature performance of electrolyte. Difluoro vinyl carbonate (dfec) 171730-81-7, a small amount of dfec can change the cycle performance and low temperature performance of the electrolyte, and has good flame retardant effect, which can significantly improve the flash point of the electrolyte. Vinyl carbonate (VC) is widely used as a new type of organic Film-forming additive and overcharge protection additive for lithium-ion batteries due to its good high and low-temperature performance and anti inflation function. It can improve the capacity and cycle life of lithium-ion batteries.
Organic sulfates, mainly represented by vinyl sulfate (DTD). DTD 1072-53-3 can inhibit the decline of initial capacity, increase the initial discharge capacity, reduce the expansion of the battery after high temperature storage, and improve the charge discharge performance and cycle times of the battery.
Sulfonates, taking 1,3- acrylonitrile lactone (PST) as an example, when 1,3- acrylonitrile lactone (PST) 21806-61-1 is added to the electrolyte, it can form a solid electrolyte phase mask on the surface of the battery electrode, inhibit the co insertion and reduction of the solvent molecules in the negative electrode, improve the cycling performance and high temperature performance of the lithium ion battery, but will result in the deterioration of the low-temperature performance of the battery.
Lithium difluorophosphate (lip02f2) 24389-25-1 and LiBOB 244761-29-3 are widely used lithium salt electrolyte additives. Lithium difluorophosphate has high electrochemical stability, which can improve the conductivity of non-aqueous electrolyte solution. Adding lithium difluorophosphate to the electrolyte of lithium secondary battery can not only improve the low-temperature output characteristics of the battery, but also inhibit the decomposition of the positive surface during high-temperature cycling and prevent the oxidation reaction of the electrolyte solution, so as to improve the output characteristics after high-temperature storage And swelling properties.