EP-4485584-B1 - ELECTRODE BINDER FOR BIOFUEL CELL
Inventors
- HANASAKI, MITSURU
- IKEHATA, RYOHSUKE
Dates
- Publication Date
- 20260513
- Application Date
- 20240327
Claims (3)
- The use of an electrode binder for producing a biofuel cell, the electrode binder comprising a polymer (A) comprising a first structural unit derived from a nonionic ethylenically unsaturated monomer (a1), a second structural unit derived from an anionic ethylenically unsaturated monomer (a2), and a third structural unit derived from a crosslinking agent (a3), wherein the nonionic ethylenically unsaturated monomer (a1) is a combination of an aromatic ethylenically unsaturated compound, a (meth)acrylic acid alkyl ester, and a polar group-containing ethylenically unsaturated carboxylic acid ester, and wherein the crosslinking agent (a3) has two or more ethylenically unsaturated bonds in one molecule.
- The use according to claim 1, wherein a content of the polymer (A) in the electrode binder is 50% by mass or more.
- The use according to claim 1, wherein the anionic ethylenically unsaturated monomer (a2) comprises one or more selected from the group consisting of an ethylenically unsaturated carboxylic acid and a salt thereof, and an ethylenically unsaturated sulfonic acid and a salt thereof.
Description
Technical Field The present invention relates to an electrode binder for a biofuel cell. Background Art As a next-generation fuel cell, research and development are being carried out on a biofuel cell that uses an enzyme or a microorganism as an electrode catalyst and generates electricity by using a biomass resource such as a sugar, an alcohol, or an organic waste liquid as a fuel (see, for example, Patent Literatures 1, 2 and 3). A biofuel cell that uses an enzyme generally generates electricity by oxidatively degrading a fuel at a negative electrode (anode) through the use of an oxidizing enzyme to extract an electron and by reducing oxygen at a positive electrode (cathode) through the use of a reducing enzyme to generate water. One known process for producing such a biofuel cell simply and at low cost is a method involving patterning an electrode material by screen printing. Specifically, the method is generally a method for forming an electrode pattern by preparing a slurry (electrode slurry) by dispersing a conductive material such as a carbon powder in a binder (electrode binder) obtained by dissolving polyvinylidene fluoride (PVDF) in an organic solvent such as N-methylpyrrolidone (NMP), and then screen-printing the slurry on a substrate and drying the same (see, for example, Patent Literature 1). Citation List Patent Literature PTL1: JP 6994184 BPTL2: JP 2021-140988 APTL3: CN 101140256 A Summary of Invention Technical Problem However, there is a concern that the electrode binder that uses NMP, which is an organic solvent, may damage a screen printing apparatus, and the environmental load of the organic solvent is also a problem. In addition, in the case of the electrode slurry that uses PVDF, it could not be necessarily said that the binding property of the conductive material is not necessarily sufficient. Furthermore, PVDF is highly water repellent, and the electrode slurry that uses PVDF also has problems such as insufficient immobilization of an enzyme on an electrode and easy inactivation of an enzyme, making it impossible to obtain a biofuel cell exhibiting sufficient output characteristics. The present invention has been made in order to solve these problems, and an object thereof is to provide an electrode binder for a biofuel cell, which can provide an electrode slurry that has a low environmental load and is suitable for screen printing and allows production of a biofuel cell that exhibits good output characteristics. Solution to Problem The present invention is based on the finding that a predetermined polymer is suitable as an electrode binder when forming an electrode for a biofuel cell by screen printing. The present invention provides the following means. [1] The use of an electrode binder for biofuel cell that comprises a polymer (A), the polymer (A) comprises a first structural unit derived from a nonionic ethylenically unsaturated monomer (a1), a second structural unit derived from an anionic ethylenically unsaturated monomer (a2), and a third structural unit derived from a crosslinking agent (a3), and the crosslinking agent (a3) has two or more ethylenically unsaturated bonds in one molecule.[2] The use of the electrode binder for a biofuel cell according to [1], wherein a content of the polymer (A) is 50% by mass or more.[3] The use of the electrode binder for a biofuel cell according to [1], wherein the anionic ethylenically unsaturated monomer (a2) comprises one or more selected from the group consisting of an ethylenically unsaturated carboxylic acid and a salt thereof, and an ethylenically unsaturated sulfonic acid and a salt thereof. Advantageous Effects of Invention According to the present invention, it is possible to provide an electrode binder for a biofuel cell, which can provide an electrode slurry that has a low environmental load and is suitable for screen printing and allows production of a biofuel cell that exhibits good output characteristics. Brief Description of Drawings [Fig. 1] Fig. 1 is a schematic cross-sectional view schematically showing an example of the configuration of a biofuel cell according to an embodiment of the present invention.[Fig. 2] Fig. 2 is a schematic cross-sectional view schematically showing a further example of the configuration of a biofuel cell according to an embodiment of the present invention.[Fig. 3] Fig. 3 is a schematic cross-sectional view schematically showing an example of the embodiment of the biofuel cell of Fig. 1. Description of Embodiments The definitions and meanings of the terms and expressions used herein will be given below. The electrode binder for a biofuel cell, the electrode binder composition for a biofuel cell, and the electrode slurry for a biofuel cell are also referred to simply as the "electrode binder," the "electrode binder composition," and the "electrode slurry," respectively. When simply referring to an "electrode," the electrode refers to an electrode in a state before an enzyme is immobilized thereo