Positive electrode active material, preparation method thereof, battery cell, and power consuming apparatus

A preparation method of a positive electrode active material, comprises the following steps:

• providing a lithium-containing phosphate precursor;
• grinding the lithium-containing phosphate precursor and a first carbon source, heating a ground material to a first temperature T1 in a protective gas atmosphere, and keeping the ground material at the first temperature T1 for a first time t1 to obtain a lithium-containing phosphate coated with a first carbon coating layer;
• and
• placing the obtained lithium-containing phosphate coated with a first carbon coating layer in a chemical vapor deposition device, heating the chemical vapor deposition device to a second temperature T2 in the protective gas atmosphere, introducing deposition gas, and then, keeping the chemical vapor deposition device at the second temperature T2 for a second time t2 to enable the deposition gas to deposit to form a second carbon coating layer, so as to obtain a positive electrode active material, wherein
• the positive electrode active material comprises the lithium-containing phosphate, a charge capacity per gram of the positive electrode active material at 25° C. is denoted as C1, the charge capacity per gram of the positive electrode active material at 60° C. is denoted as C2, both units are mAh/g, and C2/C1≥1.020.