The invention relates to the technical field of
lithium-
ion solid-state batteries, in particular to a three-dimensional
polymer modified intermediate layer for a
lithium-
ion solid-state battery and a preparation method of the three-dimensional
polymer modified intermediate layer, and the preparation method comprises the following steps: adding
polyacrylonitrile into N, N-
dimethylformamide, and stirring until the
polyacrylonitrile is completely dissolved; and then adding the modified
polyamide acid-
phosphonate copolymer, continuously stirring to obtain an electrostatic
spinning precursor solution, and carrying out electrostatic
spinning on the electrostatic
spinning precursor solution to obtain the composite
nanofiber membrane. According to the invention, the
indium-containing heterocyclic modified
diamine is used as a core
monomer of the
polyamide acid-
phosphonate copolymer, the
lithium deposition
nucleation overpotential can be reduced by the excellent lithium-loving activity of the
indium-containing heterocyclic modified
diamine, the lithium is enabled to be compact and free of dendritic
crystal deposition, and the
indium-containing heterocyclic group is uniformly dispersed in a three-dimensional framework through a cross-linked network of the modified
polyamide acid-
phosphonate copolymer, so that the performance of the
polymer is improved. The contact interface of the intermediate layer and the
lithium metal forms a global uniform lithium-loving site, and concentrated deposition of lithium atoms caused by local lithium-loving activity difference is avoided.