The invention discloses a composite coated
graphite negative
electrode material, a preparation method thereof and a
lithium ion solid-state battery, and belongs to the technical field of
lithium ion solid-state batteries, the composite coated
graphite negative
electrode material comprises a
graphite matrix and a
composite coating layer, and the
composite coating layer comprises an inner layer amorphous
lithium chloride and an outer layer nanocrystalline LiF / Li3N composite phase. Mixing graphite,
lithium chloride containing
crystal water and
ammonium fluoride to obtain a mixed material; placing the mixed material in a
microwave reaction cavity, heating the mixed material to 600-700 DEG C at the
microwave power of 800-1200 W in an H2 / Ar mixed
atmosphere, and keeping the temperature for 20-60 minutes; and cooling the sintered mixed material,
grinding, and sieving with a 100-300 mesh
sieve to obtain the composite coated graphite negative
electrode material with a
coating layer thickness of 10-50 nm. The invention provides an innovative amorphous LiCl / nanocrystalline LiF-Li3N gradient
coating layer design, the performance of the
lithium ion battery is remarkably improved by optimizing an
ion migration path, enhancing the interface stability and reducing the process cost, and a new
engineering way is provided for realizing
high magnification and long cycle performance of the
sulfide all-
solid-state battery.