Gel polymer electrolyte for lithium ion battery, and preparation method thereof

The invention discloses a gel polymer electrolyte for a lithium ion battery, and a preparation method thereof. The gel polymer electrode is composed of a polymer film as a substrate, and an electrolyte adsorbed to the polymer film; and the polymer film is made through the following steps: co-dissolving Carbomer resin, polyvinylidene fluoride and cellulose acetate butyrate in a solvent, mechanically stirring to form a liquid, coating the liquid, and solidifying the coated liquid on a polyolefin micro-porous film. The preparation method of the gel polymer electrolyte comprises the following steps: co-dissolving polyvinylidene fluoride and cellulose acetate butyrate in the solvent to prepare a liquid 1, adding the Carbomer resin to the liquid, fully stirring to form a liquid 2, immersing the polyolefin micro-porous film in the liquid 2, drying, immersing the dried polymer film in the electrolyte, and taking out the immersed film. The polymer lithium ion battery comprises the gel polymer electrolyte, a positive electrode and a negative electrode. The gel polymer electrolyte has the advantages of thermal contraction resistance, high conductivity and high electrochemical stability.