| abstract |
The application provides a positive electrode active material, a positive electrode sheet, an electrochemical energy storage device and a new energy vehicle. The positive electrode active material is Li x Ni y Co z M k Me p Or Am or Li x Ni y Co z M k Me p O r Am with a coating layer on the surface , and the positive active material is a single crystalline or quasi-single-crystal particles, and the particle size D n 10 of the positive electrode active material satisfies: 0.3 μm≦D n 10 ≦2 μm. The theoretical specific surface area BET 1 of the positive electrode active material and the real specific surface area BET 2 of the positive electrode active material satisfy: 0.3≤(BET 2 -BET 1 )/BET 1 ≤5.5; wherein, BET 1 =6/(ρ×D v 50) . By reasonably controlling the particle morphology of the positive electrode active material and the number of micropowders in the positive electrode active material, the present application effectively reduces the side reaction between the positive electrode active material and the electrolyte, reduces the gas production of the electrochemical energy storage device, and can improve the electrochemical performance. The storage performance of the energy storage device does not deteriorate the energy density, cycle performance and rate performance of the electrochemical energy storage device. |