Composite graphite material, method for preparing same, negative electrode sheet, secondary battery, battery module, battery pack, and electrical apparatus

A method for preparing a composite graphite material, comprising steps of:

• S10, providing a coke powder or the coke powder added with a raw material powder of a kinetic carbon material, and graphitizing the coke powder or the coke powder added with the raw material powder of the kinetic carbon material to obtain a bulk particle, wherein the bulk particle is a secondary particle formed by aggregation of more than two primary particles, and the bulk particle comprises artificial graphite;
• and
• S20, mixing the bulk particle with an organic carbon source, or mixing the bulk particle with the organic carbon source and the raw material powder of the kinetic carbon material, and forming a cladding layer comprising amorphous carbon on at least a partial surface of the bulk particle after carbonization, to obtain the composite graphite material,
• wherein the raw material powder of the kinetic carbon material is added in at least one of steps S10 and S20, a raw material of the kinetic carbon material is selected from one or more of hard carbon, micro-expanded graphite, expanded graphite, or graphene, an interlayer distance d002 between crystal planes of a raw material (002) of the kinetic carbon material is greater than or equal to 0.3358 nm, and
• an air oxidation temperature T0 of a resulting composite graphite material is from 630° C. to 730° C., the air oxidation temperature T0 is a temperature corresponding to an intersection of two tangents at two points corresponding to 500° C. and a temperature T1 respectively on a thermogravimetric curve of the composite graphite material, the temperature T1 is a peak temperature of a peak with a largest area in a differential thermogravimetric curve of the composite graphite material, and the thermogravimetric curve and the differential thermogravimetric curve are obtained by thermogravimetric analysis under following conditions:
• sample mass:
• 10±0.05 mg, purge gas:
• air at a gas flow rate of 60 mL/min, heating rate:
• 5° C./min, and a test temperature ranging from 35° C. to 950° C.