Functionalized lithium battery diaphragm as well as preparation method and application thereof

The invention discloses a functionalized lithium battery diaphragm as well as a preparation method and application thereof. The invention discloses a lithium battery diaphragm and a preparation method thereof. The lithium battery diaphragm comprises a base membrane and a functional layer. The functional layer at least comprises a functional component 1, the functional component 1 is selected from at least one of Li1-x1Ti1-x1Ax1OPO4, Li1-x1Ti1-x1Ax1PO5, Li2-x2Ti1-x2Ax2OM1O4 and Li2-x2Ti1-x2Ax2M1O5, 0 < = x1 < = 0.7, 0 < = x2 < = 1, A comprises at least one of Nb, Ta and Sb, and M1 is at least one of Si and Ge. The functional layer can also comprise a functional component 2. The functional layer is formed by coating a functional component 1 or mixed component slurry composed of the functional component 1 and a functional component 2, the slurry comprises, by weight, 5%-45% of a coating material and 55%-95% of a solvent, and the coating material comprises, by weight, 100 parts of the functional component, 0.3-0.