Positive electrode material and lithium ion secondary battery

Abstract

The invention provides a positive electrode material and a lithium ion secondary battery. The positive electrode material includes lithium cobaltate LiCoO2 (LCO) and lithium iron manganese phosphate LiFexMn1-xPO4 (LFMP), wherein 0<x<=0.4; the mass ratio of lithium iron manganese phosphate LiFexMn1-xPO4 to lithium cobaltate LiCoO2 is m, and 0<m<=0.45; lithium iron manganese phosphate LiFexMn1-xPO4 is polycrystalline particles having an olivine structure; lithium cobaltate LiCoO2 is polycrystalline particles having a layered structure; the average particle size D50 of the polycrystalline particles of lithium iron manganese phosphate LiFexMn1-xPO4 is less than the average particle size D50 of the polycrystalline particles of lithium cobaltate LiCoO2, and the polycrystalline particles of lithium iron manganese phosphate LiFexMn1-xPO4 are filled between the polycrystalline particles of lithium cobaltate LiCoO2. The lithium ion secondary battery includes the positive electrode material. The lithium ion secondary battery has high voltage platform and high energy density, and besides, has good multiplying power performance, cycle performance and safety performance.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a positive electrode material and a lithium ion secondary battery. Background technique [0002] With the rapid development of transportation, communication and information industries and the increasingly severe energy crisis, electric vehicles and various portable devices have put forward an urgent demand for high-performance alternative energy sources. As a chemical power source, lithium-ion secondary batteries have become an ideal choice for alternative energy sources due to their advantages such as high energy density, good cycle performance, and low self-discharge rate. While lithium-ion secondary batteries have many advantages, energy density, safety, production cost and cycle life have become the key factors restricting their development. The above factors are closely related to the physical properties, chemical properties, electrochemical properties and compatibility w...

AI Technical Summary

Problems solved by technology

The smaller the particle size of LCO, the more lithium will be delithiated at the same voltage, resulting in poorer structural stability and increased electrolyte consumption.

In addition to obtaining higher structural stability and thermal stability, LCO with a larger particle size is also conducive to achieving a larger compacted density, thereby obtaining a higher energy density and a larger usable gram capacity, but it will Reduce the ability of lithium-ion secondary batteries to absorb electrolyte, resulting in the occurrence of liquid swelling behavior of lithium-ion secondary batteries

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