The invention relates to the technical field of
lithium battery manufacturing, in particular to a composite active material, a preparation method and an obtained
lithium-
iron disulfide battery positive plate. The composite active material is of a core-shell structure of
cobalt disulfide and
iron disulfide, the core-shell structure is characterized in that the
cobalt disulfide is coated with the
iron disulfide, the particle size of the
cobalt disulfide is 2-5 microns, and the particle size of the composite active material is 12-20 microns. According to the method, the characteristic that physical and chemical properties of cobalt disulfide and iron disulfide are similar is utilized, cobalt disulfide is added in the iron disulfide preparation process through a
precipitation method, cobalt disulfide serves as a precursor for preparing iron disulfide, cobalt disulfide serves as the center and extends outwards to synthesize iron disulfide, and then
sulfur removal treatment is conducted. A
lithium-iron disulfide battery positive plate prepared from the composite active material is high in
conductivity and low in self-
discharge rate, and a battery assembled by the positive plate material is low in
internal resistance and excellent in storage performance. And the composite active material also improves the
discharge platform of the battery and the
pulse discharge performance of the battery.