Cathode slurry composition for secondary battery, cathode for secondary battery produced by using same and secondary battery

Abstract

The present invention relates to a cathode slurry composition for a secondary battery. The cathode slurry composition for the secondary battery comprises a cathode active material; a carbon-based conductive material having a specific surface area (BET) of 100 to 200 m2 / g; a binder; and a nitrile-based copolymer which has an electrolyte swelling degree defined by formula (1) below of 200% or lower,and which does not contain a functional group other than a cyano group. The present invention also provides a cathode for the secondary battery produced by using the cathode slurry composition and the secondary battery. In a Formula (1): electrolyte swelling degree (%) = {(W1-W0) / W0}*100, W0 is the initial weight of a polymer film produced from the nitrile-based copolymer, and W1 is the weight ofthe polymer film measured after storing the polymer film in an electrolyte at 60 DEG C for 48 hours.

Description

technical field [0001] Cross References to Related Applications [0002] This application claims the benefit of Korean Patent Application No. 10-2017-0158629 and No. 10-2017-0158628 filed with the Korean Intellectual Property Office on November 24, 2017, the disclosures of which are incorporated by reference in their entirety here. [0003] technical field [0004] The present invention relates to a positive electrode slurry composition for a secondary battery, a positive electrode, and a secondary battery, and more particularly, to a positive electrode slurry composition for a secondary battery having excellent high-temperature characteristics and a preparation using the composition positive electrode and lithium secondary battery. Background technique [0005] A positive electrode for a secondary battery is generally prepared by coating a positive electrode current collector with a positive electrode slurry composition including a positive electrode active material, ...

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Problems solved by technology

[0008] However, in the case of using the nitrile-based copolymer described in Patent Document 1, the affinity with the electrolyte solution is increased due to the presence of the hydrophilic functional group, and as a result, since the nitrile-based copolymer is exposed to high-temperature conditions during battery operation Battery adhesion decreases while being swollen by the electrolyte solution, so high-temperature characteristics may deteriorate

In addition, in Patent Document 1, a nitrile-based copolymer has been used as an adhesive, but, for the nitrile-based copolymer, since its adhesiveness is lower than that of polyvinylidene fluoride even if a functional group is used, since polyvinylidene fluoride The amount of vinyl fluoride binder is reduced, resulting in a decrease in electrode adhesion, and as a result, the high temperature characteristics are further deteriorated

To solve this limitation, it is necessary to increase the amount of binder, however, in the case of increasing the amount of binder, the amount of positive electrode active material decreases, so the electrochemical properties become insufficient

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