US 10,476,082 B2 · Surface coated positive electrode active material, preparation method thereof and lithium secondary battery including the same

Abstract

The present invention relates to a surface coated positive electrode active material, a preparation method thereof, and a lithium secondary battery including the same. More specifically, it relates to a positive electrode active material of which surface is coated with a nanofilm including polyimide (PI) and carbon black, a preparation method thereof, and a lithium secondary battery including the same. The positive electrode active material of which surface is coated with the nanofilm according to the present invention is capable of preventing direct contact of the positive electrode active material with an electrolyte thereby suppressing a side reaction between the positive electrode active material and the electrolyte, and as a result, a lifespan property of a lithium secondary battery using a positive electrode including the same may be significantly improved, and particularly, a lifespan property and conductivity are capable of being enhanced under a high temperature and high voltage condition.

Claims17

Dependent claims

A lithium secondary battery comprising:

a positive electrode;
a negative electrode;
and a separator provided between the positive electrode and the negative electrode;
wherein the positive electrode includes a surface coated positive electrode active material comprising:
a positive electrode active material;
and
a nanofilm, including polyimide (PI) and carbon black, coated on a surface of the positive electrode active material;
wherein the nanofilm includes the polyimide and the carbon black in a weight ratio of 1:0.5 to 1:5;
wherein an iodine number of the carbon black measured in accordance with the ASTM D-1510 is from 200 mg/g to 400 mg/g;
wherein an oil absorption number of the carbon black measured in accordance with the ASTM D-2414 is from 100 cc/100 g to 200 cc/100 g;
wherein the lithium secondary battery has a capacity retention rate of 97% or more after 50 cycles, in each of which the lithium secondary battery was charged at a charging rate of 0.5 C and discharged at a rate of 1 C, in a voltage range of 3 V to 4.4 V, at 45° C.

8 more elements

Dependencies are inferred from the claim text.

Surface coated positive electrode active material, preparation method thereof and lithium secondary battery including the same

Life of this patent

Surface coated positive electrode active material, preparation method thereof and lithium secondary battery including the same

Life of this patent

Abstract

Claims17