Dai-Ichi Kogyo Seiyaku Co., Ltd.

Atsushi Sanuki

Masanori Ohzaki

Shiho Nakamura

Ryo Kakubari

Miho Shibata

A negative electrode of a nonaqueous electrolyte secondary battery, which is provided with a collector and a negative electrode active material layer that is formed on the collector, and which is characterized in that: the negative electrode active material layer contains a carbon-based negative electrode active material, a silicon-based negative electrode active material, a conductive agent and a predetermined carboxy methylcellulose or a salt thereof; the content of the carboxy methylcellulose or a salt thereof is from 4% by mass to 15% by mass (inclusive) relative to the total mass of the negative electrode active material layer; and the content of the silicon-based negative electrode active material relative to the total content of the carbon-based negative electrode active material and the silicon-based negative electrode active material is from 3% by mass to 19% by mass (inclusive).

Negative electrode of nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

Provided is a carboxymethyl cellulose or a salt thereof, in which when the carboxymethyl cellulose or the salt thereof is used as a binding agent for an electrode of a nonaqueous electrolyte secondary battery, defects, such as pinholes, on a surface of the electrode are reduced and a battery including the electrode has a good capacity retention. A method for producing a carboxymethyl cellulose or a salt thereof includes an alkali cellulose formation step (step 1) of allowing cellulose and an alkali to react with each other in the presence of a mixed solvent containing water and an organic solvent, an etherification step (step 2) of allowing the resulting alkali cellulose and an etherifying agent to react with each other, a purification step (step 3) of washing and drying the resulting reaction mixture, and a pulverization step (step 4) of pulverizing the resulting purified product. In the method, the step 1 is conducted for a reaction time of 60 minutes or more and 120 minutes or less under conditions of a pH of 9 or more and a reaction temperature of 5&#xb0; C. or higher and 25&#xb0; C. or lower.

Method for producing carboxymethyl cellulose or salt thereof, and binding agent for electrode

A manufacturing method which includes: (1) an alkali cellulose reaction step wherein a mixed solvent having a mixing ratio (a mass ratio) of an alcohol having a carbon number of 3 or less and water of 75:25 to 95:5 is used, and the concentration of the base to the water is 25 to 40 mass %; (2) an etherification reaction step wherein a reaction is carried out under an excess base of 0.2 to 0.5 moles per unit of an anhydroglucose of the cellulose; (3) a neutralization step wherein acid is added to adjust the pH of the reaction mixture to 6.0 to 8.0; and (4) a heating step wherein the mixed solvent is removed, and a base is added to adjust the pH of the reaction mixture to 8.0 to 9.0, and then a heat treatment is performed at 40 to 70&#xb0; C. for 30 to 120 minutes.

Manufacturing method of carboxymethyl cellulose salt for electrode of nonaqueous electrolyte secondary battery, electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

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Kyoto, Japan

Atsushi Sanuki