Method for producing carboxymethyl cellulose salt for electrodes of nonaqueous electrolyte secondary batteries, electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

Abstract

The purpose of the present invention is to provide a carboxymethyl cellulose salt for electrodes of nonaqueous electrolyte secondary batteries, which is capable of achieving a good balance between prevention of defects such as streaks and pin holes on a coated electrode surface and excellent bonding strength to a collector or excellent bonding strength between active materials. A production method which comprises: (1) an alkali cellulose formation reaction step wherein a mixed solvent that contains an alcohol having 3 or less carbon atoms and water at a mixing ratio (mass ratio) of from 75:25 to 95:5 is used and the alkali concentration relative to water is 25-40% by mass; (2) an etherification reaction step wherein a reaction is carried out in the presence of an excess alkali of 0.2-0.5 mol per unit of an anhydroglucose of the cellulose; (3) a neutralization step wherein an acid is added after the etherification reaction so that the pH of the reaction mixture is adjusted to 6.0-8.0; and (4) a heating step wherein the mixed solvent is removed and an alkali is added after the neutralization step so that the pH of the reaction mixture is adjusted to 8.0-9.0, and subsequently, a heat treatment is carried out at 40-70 DEG C for 30-120 minutes.

Description

technical field [0001] The invention relates to a method for producing carboxymethyl cellulose salt for an electrode of a non-aqueous electrolyte secondary battery. Background technique [0002] In recent years, electronic devices, especially portable devices such as mobile phones, personal digital assistants (PDAs), and notebook computers have been miniaturized, lightweight, thinned, and high-performance, and the popularity of portable devices is increasing progress. With the diversification of the application range of such portable devices, batteries for driving these portable devices are becoming very important components. Among batteries, nonaqueous electrolyte secondary batteries represented by lithium ion secondary batteries, which have high energy density and high capacity, have been widely used. [0003] Generally, a nonaqueous electrolyte secondary battery is manufactured as follows. That is, on the surface of the metal foil as the current collector base material...

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Problems solved by technology

It is described in this document that if an existing aqueous solution of carboxymethylcellulose or its salt is prepared, gel particles derived from carboxymethylcellulose or its salt will remain in the aqueous solution as undissolved matter, but by treating Carboxymethyl cellulose or its salt is subjected to mechanical dry or wet pulverization treatment, in the aqueous solution of the mechanical pulverization treatment product of carboxymethyl cellulose or its salt, the above-mentioned gel particles will be miniaturized, as a result, If the electrode is formed using an aqueous solution of a mechanically pulverized product of carboxymethylcellulose or its salt, it is possible to suppress coarse undissolved matter that would cause streaky defects (streaks) or peeling on the electrode surface , pinhole, etc.

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