The invention discloses a preparation method of a battery-grade
graphite-
activated carbon composite material. The preparation method comprises the steps that 1,
plant raw materials are washed clean with water and then contained in a
metal tank, the
metal tank is sealed and put into a
muffle furnace, heating is conducted at the constant temperature of 450 DEG C to 650 DEG C, the temperature is naturally decreased to
room temperature, and black
solid activated carbon is obtained; 2, the obtained black
solid activated carbon and
graphite are put into a ball milling tank according to the
mass ratio of 3:1-1:1, an appropriate amount of
hydrochloric acid with the concentration of 0.2 M to1.0 M, an appropriate amount of
sulfuric acid with the concentration of 0.1 M to 0.5 M, an appropriate amount of
acetic acid with the concentration of 0.5 M to 1.2 M and an appropriate amount of water are sequentially added into the ball milling tank, ball milling is conducted for 0.5 hour to 2 hours under the condition that the ball-material ratio is equal to 1:10-1:20, and then
acid washing and
water washing are sequentially conducted, wherein
sulfuric acid,
hydrochloric acid and
acetic acid are subjected to ball-milling washing three times to five times separately, and the water is subjected to ball-milling washing until the pH value of eluate is 6.8 to 7.2; 3, the washed
graphite-activated carbon mixture is subjected to suction
filtration and dried in an atmospheric environment, and the battery-grade graphite-activated carbon
composite material is obtained. The preparation method has the advantages of being simple in process, rich in raw materials, short in manufacturing cycle and low in
energy consumption and has good
economic benefits, environmental benefits and
social benefits.