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Cyclotriphosphazene compounds can be used to improve lithium electronic safety

2019-03-14 来源:亚科官网

In recent years, with the development and popularization of portable devices such as mobile phones and notebook computers, and the continued rise of the new energy vehicle market, lithium-ion batteries have been widely used as an important energy source. However, lithium-ion batteries also have the characteristics of flammable and explosive. In order to improve the safety of lithium-ion batteries, the development of electrolytes that are difficult to burn or even non-combustible has become a research hotspot in this field. Adding a high boiling point, high flash point, and good electrochemical stability to the electrolyte can effectively improve and improve the stability of the lithium ion battery electrolyte, thereby improving the safety performance of the lithium ion battery.

Safety research of Lithium-ion battery

Adding electrolyte flame retardant can improve the safety of the battery, but adding flame retardant additives may cause side effects on other aspects of the battery, and the cyclotriphosphazene compound is characterized by high efficiency flame retardancy, chemical and electrochemical properties. And its structure has a plurality of active sites, and a cyclotriphosphazene compound containing different groups can be obtained by molecular design, and thus has received more and more attention in the research of lithium ion battery safety.

What is cyclotriphosphazene?

Cyclotriphosphazene is a class of inorganic compounds with a stable six-membered heterocyclic ring and a conjugated structure. Among them, hexachlorocyclotriphosphazene is the simplest and most basic compound. Hexachlorocyclotriphosphazene has good thermal stability and chemical inertness. It is difficult to be oxidized when placed in the air. The presence of chlorine atoms makes it viable and chemically active. Under certain conditions, it is easy to be used by various pros. Substituted by a nuclear reagent, many phosphazene derivatives having specific functions are produced.

Synthesis of cyclotriphosphazene

The conventional synthesis method of hexachlorocyclotriphosphazene is based on phosphorus pentachloride and ammonium chloride as a raw material, and an appropriate catalyst is added in an inert solvent such as tetrachloroethane (or chlorobenzene), and heated to reflux to obtain a crude product. After a series of purification treatments, pure white or light yellow hexachlorocyclotriphosphazene crystals can be obtained.

Flame retardant mechanism of cyclotriphosphazene compounds

The cyclotriphosphazene compound is a six-membered cyclic compound formed by alternating nitrogen and phosphorus single and double bonds, which has a special molecular structure and stable chemical structure, so that it has excellent thermal stability. The molecule contains phosphorus and nitrogen flame retardant components, which have synergistic resistance, and phosphazene can be endothermicly decomposed to form phosphate, metaphosphate and polyphosphate and non-flammable gas, forming non-volatile on the surface of the flame retardant material. Sexual protective film to block air, thus inhibiting combustion.

Fluorine-containing triphosphazene has the best flame retardant effect

Pentafluoroethoxyphosphazene has two flame retardant elements, P and F, which have synergistic effect, can reduce the amount of additives, improve flame retardant efficiency, can significantly improve the safety performance of the electrolyte, and completely prevent the safety hazard of fire, combustion and explosion caused by abuse and overcharge; at the same time, the presence of F element helps to form an excellent SEI film at the electrode interface, improves the compatibility between the electrolyte and the active material, and stabilizes the electrochemical performance of the electrode. Resistant to oxidation resistance, can significantly improve the cycle performance of high voltage batteries.

Fluorine-containing triphosphazene has flame retardancy and electrochemical stability due to its structural specificity, and it can be effectively added to the electrolyte of lithium battery to improve the thermal stability and flammability of the electrolyte. It has been one of the research hotspots of lithium ion battery flame retardants, especially pentafluoroethoxycyclotriphosphazene, which has a good flame retardant effect and has been regarded as the future choice of lithium battery flame retardant market.

Related links: Ethoxy(pentafluoro)cyclotriphosphazene

Edited by Suzhou Yacoo Science Co., Ltd.