Phosphorus-containing flame-retardant thermoplastic polyurethane, solid electrolyte and lithium battery

Abstract

The invention discloses phosphorus-containing flame-retardant thermoplastic polyurethane, solid electrolyte and a lithium battery. The polyhydric alcohol raw material in the phosphorus-containing flame-retardant thermoplastic polyurethane contains phosphorus-containing polycarbonate dihydric alcohol. The solid electrolyte contains 40%-90% of the phosphorus-containing flame-retardant thermoplasticpolyurethane and 10%-60% of lithium salt in percentage by weight. A preparation method of an electrolyte membrane of the solid electrolyte comprises the steps of dissolving the phosphorus-containing flame-retardant thermoplastic polyurethane and the lithium salt in a solvent to obtain film casting liquid, and preparing the electrolyte membrane by virtue of the film casting liquid. The electrolytehas high ionic conductivity, heat resistance and flame-retardant stability.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a phosphorus-containing flame-retardant thermoplastic polyurethane, a solid electrolyte and a lithium battery thereof. Background technique [0002] Lithium-ion batteries (LIBs) are considered to be one of the most important energy storage technologies. As the energy density of batteries increases, battery safety becomes more important. Accidents related to LIB fires and explosions occur frequently worldwide. Some have caused serious threats to human life and health, and these incidents remind people that safety is a prerequisite for batteries and a serious problem that needs to be solved before applying high-energy battery systems in the future. Solid polymer electrolytes (SPEs) have been extensively studied because they can overcome some of the safety issues in lithium-ion batteries (LIBs) caused by liquid electrolytes, such as leakage of organic solvents, flammabil...

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Problems solved by technology

Chinese patent CN102020780 A discloses an all-solid polymer electrolyte membrane, which is prepared by using polyethylene oxide and liquid crystal polymers containing sulfonate ions. The preparation process of this work requires the use of a large amount of toxic solvents such as acetonitrile. There are great shortcomings in the protection of the environment, and it does not match the national environmental protection policies in recent years and cannot be supported by the state.

For example, Chinese patent CN101280104A discloses that a polymer material is used in the electrolyte. The method is to disperse the polysiloxane in the water-based polyurethane by the dispersion method of the blending method, and then add the mixed solution to the conductive salt and gradually dissolve it. In this way, the aqueous polyurethane polysiloxane solid electrolyte is prepared, but the electrolyte prepared by this method has disadvantages. It can only be used in batteries by absorbing the electrolyte to form a gel electrolyte. However, the gel electrolyte usually still exists after long-term use There is a problem with liquid precipitation, and its essence is not a real all-solid electrolyte

Chinese patent CN106532116A discloses a high-temperature-resistant solid polymer electrolyte, which is obtained by radical polymerization induced by ultraviolet light, but the solid polymer electrolyte obtained by this method has low ion conductivity, and acetonitrile is used in the preparation process Toxic solvents, not environmentally friendly

Chinese patent CN102738426 A discloses a high-temperature-resistant lithium battery. The electrolyte membrane is prepared by the thermosetting reaction of polyimide and polycarbosilane, which endows the battery with high-temperature resistance. However, the electrolyte membrane prepared by this method is brittle and has poor safety. And in the process, a large amount of toxic solvents such as N-methylpyrrolidone, dimethylacetamide and dimethylformamide still need to be used, which is extremely harmful to the environment and construction personnel

Commercial lithium batteries use organic liquid electrolytes. The electrolyte and electrode materials are prone to side reactions during charge and discharge, resulting in irreversible decline in battery capacity. At the same time, the organic liquid electrolyte will volatilize, dry up, and leak during the long-term service of the battery. and other phenomena, affecting battery life

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