COMPOSITE GRAPHITE MATERIAL, SECONDARY BATTERY, APPARATUS AND PREPARATION METHOD THEREOF

The present application discloses a composite graphite material, a secondary battery, an apparatus and a preparation method thereof. The composite graphite material includes a core material and a coating layer coating at least a part of the surface of the core material, the core material including graphite; wherein the absolute value K of zeta potential of the composite graphite material in deionized water with a pH of 7 is at least 20 mV. The use of the composite graphite material provided by the present application can improve the cohesion and bonding force of the negative electrode plate, thereby reducing the cyclic expansion of the secondary battery.