Electrolyte film and porous substrate and preparation thereof, lithium ion secondary battery

Abstract

The invention relates to a gel-type polymer electrolyte film for a lithium ion secondary battery and a process for preparation, and a lithium ion secondary battery which contains the electrolyte film. The gel-type polymer electrolyte film for the lithium ion secondary battery can be obtained through the following method: preparing polyvinylidene fluoride nonwoven through the electrostatic spinning method, making the surface of the polyvinylidene fluoride nonwoven activate through radiating electron beams for the obtained the polyvinylidene fluoride nonwoven in air, contacting a methyl methacrylate monomer and the polyvinylidene fluoride nonwoven after the surface activation, thereby obtaining the polyvinylidene fluoride nonwoven whose surface is grafted with polymethyl methacryate. Furthermore, the lithium ion battery electrolyte film can be obtained through making the polyvinylidene fluoride nonwoven whose surface is grafted with polymethyl methacryate absorbs a certain amount of electrolytic solution. The invention develops the respective advantages in the lithium ion battery owing to using the polyvinylidene fluoride nonwoven whose surface is grafted with polymethyl methacryate, compared with singly using polyvinylidene fluoride or polymethyl methacryate or the both simple composite, and eliminates the disadvantages caused by singly using one material or several materials. The electrolyte film has high ion electrical conductivity under ambient temperature after absorbing the electrolytic solution, and can manifest excellent heavy-current discharge performance and circulation stability after being assembled in the batteries.

Description

technical field [0001] The invention relates to an electrolyte membrane for a lithium ion secondary battery and a preparation method thereof, in particular to a gel-type polymer electrolyte membrane for a lithium ion secondary battery and a preparation method thereof, and a lithium electrolyte membrane comprising the above electrolyte membrane ion secondary battery. Background technique [0002] The research of high energy density battery is getting more and more attention along with the improvement of people's requirements for environmental quality, and as an important part of high energy density battery, electrolyte becomes the key to development. Due to the poor electrochemical stability of the batteries used in the past, it is a good solution to use polymer electrolytes in high energy density battery systems. The room temperature ionic conductivity of all-solid polymer electrolytes has so far been unable to reach 10 -3 S cm -1 The level of application (Komiya, Hayashi...

AI Technical Summary

Problems solved by technology

[0003] At present, the gel-type polymer electrolyte has porous polyvinylidene fluoride as the matrix (Mohamed N.S, ArofA.K. Journal of Power Sources. 2004, 132: 229), and the impregnated porous electrolyte has a faster charge and discharge rate than the porous polyvinylidene fluoride. Olefin separator has good ability and good mechanical properties, but its affinity for electrolyte is poor, and the electrolyte is easy to leak during the use of the battery

A copolymer formed by introducing hexafluoropropylene units by reducing the crystallinity of polyvinylidene fluoride (Stephan A.M, Renganathan N.G., Gopukumar S., Dale-Teeters. Materials Chemistry and Physics. 2004, 8:6), although in The liquid absorption ability has been improved to a certain extent, but it still cannot fundamentally solve the problem of weak liquid absorption ability

[0004] Moreover, the above-mentioned fluorine-containing gel type polymer electrolyte membrane has poor compatibility with electrodes, and the interface resistance is large.

The gel-type polymer electrolyte of polymethyl methacrylate can absorb a large amount of electrolyte (Zhou, Y.F., Xie, S., Ge, X.W., Chen, C.H., Amine, K.Journal of Applied Electrochemistry.2004, 34 : 1119), and has good compatibility with electrodes and low interface resistance, but its mechanical properties are poor

Blending polyvinylidene fluoride and polymethyl methacrylate (Nicotera I, CoppolaL, Oliviero C, Castriota M, Cazzanelli E. Solid State Ionics.2006, 177:581), can better synthesize polyvinylidene fluoride And the performance of polymethyl methacrylate, but after using this electrolyte membrane for a period of time, severe phase separation will occur, which will reduce the performance of the battery

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