The invention belongs to the technical field of a
lithium battery
solid electrolyte, and particularly provides a cross-linked PEO-based composite
solid electrolyte and a preparation method thereof, which are used for improving the
mechanical strength and electrochemical performance of the PEO-based
solid electrolyte. The cross-linked PEO-based composite solid electrolyte comprises poly (
ethylene oxide) (PEO),
lithium bis (trifluoromethylsulfonyl)
imide (LiTFSI) and bis (acetylacetonate) diisopropyl
titanate, the bis (acetylacetonate) diisopropyl
titanate is used as a cross-linking agent, and the
mass of the poly (
ethylene oxide) (PEO) is used as a reference, so that the
mass of the poly (
ethylene oxide) (PEO) and the
mass of the
lithium bis (trifluoromethylsulfonyl)
imide (LiTFSI) are uniformly distributed, and the mass of the lithium bis (trifluoromethylsulfonyl)
imide (LiTFSI) is uniformly distributed on the basis of the mass of the poly (
ethylene oxide) (PEO). The content of the bis (acetylacetonate) diisopropyl
titanate is 3 to 5 weight percent of that of the
polyethylene oxide. According to the invention, bis (acetylacetonate) diisopropyl titanate (TAA) is creatively provided as a cross-linking agent of the PEO-based composite solid electrolyte, and the introduction of the cross-linking agent can significantly increase the
mechanical strength of PEO and increase the stability of the PEO-based solid electrolyte to
lithium metal, so that the cycle life is prolonged, and the electrochemical performance is improved.