The invention belongs to the production field of
lithium batteries, in particular to a
lithium ion battery separator with low
thermal shrinkage rate and a preparation method therefor. The surface of the
lithium ion battery separator with the low
thermal shrinkage rate is uniformly coated with a
cellulose layer; and a
porous membrane base material is any one of a PE single-layer membrane, a PP single-layer membrane or a PP / PF / PP three-layer co-extruding membrane. The preparation method provided by the invention is as follows:
cellulose dissolving, mixing the
cellulose, strong alkali,
urea and water at a proper proportion to obtain a cellulose
carbamate solution; cellulose
coating,
coating the solution on the surface of the
porous membrane base material and
drying; and cellulose regenerating, immersing the
porous membrane base material which is coated with the cellulose into a
sulfuric acid solution at a certain concentration to regenerate, and
drying. The
lithium ion battery separator and the preparation method therefor have the beneficial effects that: the
coating layer is in tight contact with the porous membrane base material without falling easily; the
thermal shrinkage rate of the diaphragm is greatly reduced; the
lithium ion battery separator is higher in
electrolyte wettability; the capacity
fading of the battery can be effectively reduced; and the cellulose of waste batteries can be dissolved and reused, so that the
lithium ion battery separator is energy-saving and environment-friendly.