Composite cathode active material and lithium ion secondary battery

Abstract

The invention provides a composite positive electrode active material and a lithium ion secondary battery. The composite positive electrode active material comprises positive electrode active material particles, and a coating material which is positioned on the external of the positive electrode active material particles for coating the positive electrode active material particles. The positive electrode active material particles are layered lithium composite oxide; the general formula of the layered lithium composite oxide is Li1+xNiaCobM (1-a-b)Y2, wherein x is greater than or equal to minus 0.1 and less than or equal to 0.2; a is greater than or equal to 0 and less than or equal to 1, b is greater than or equal to 0.05 and less than or equal to 1, and a+b is greater than or equal to 0.05 and less than or equal to 1; M is selected from one or more of Mg, Zn, Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo or Zr; Y is selected from one or more of O, or F; the bulk structure of the coating material is P4 / mbm space group; and the lithium ion secondary battery comprises the composite positive electrode active material. The lithium ion secondary battery is higher in energy density and better in cycle performance under high voltage.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a composite positive electrode active material and a lithium ion secondary battery. Background technique [0002] As an environmentally friendly energy storage device, lithium-ion secondary batteries have higher energy density than lead-acid batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, and they also have the advantages of small self-discharge and long cycle life. Has been widely used in consumer electronics and automotive fields. In the automotive field, in order to alleviate or solve the environmental problems caused by fuel vehicles, pure electric vehicles or hybrid electric vehicles have emerged. However, the energy density and power density of lithium-ion secondary batteries are the main bottlenecks restricting the development of electric vehicles. At the same time, electronic technology products are constantly being updated, posing higher chall...

AI Technical Summary

Problems solved by technology

[0004] The Chinese patent application publication number CN103094553A published on May 8, 2013 discloses a 1+x m 1-x o 2 The surface of the positive electrode material is coated with AlF 3 modification method, but the resulting AlF 3 Belonging to the α structure, the cycle performance of lithium-ion secondary batteries is poor

The international patent application publication number WO2006 / 109930A1 published on October 19, 2006 discloses a method of coating the positive electrode material with fluoride and performing an electrochemical test at a voltage range of 3.0V to 4.5V. compounds including AlF 3 , but the AlF 3 Belonging to the α structure, the cycle performance of lithium-ion secondary batteries is poor

Although the cladding material adopted in the prior art and the cladding method used have certain improvement to the electrochemical performance of lithium-ion secondary battery, the charging cut-off voltage of lithium-ion secondary battery is still only limited to 4.5V and the following

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