Radical scavenger, method for preparing same, and membrane-electrode assembly containing same

Patent metadata

Field	Value
Publication number	US-12424647-B2
Application number	US-202017607408-A
Country	US
Kind code	B2
Filing date	May 8, 2020
Priority date	May 8, 2019
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

Disclosed are a radical scavenger, a method for preparing same, and a membrane-electrode assembly containing same, wherein the radical scavenger can maintain the performance of a fuel cell for a long time and enhance the lifespan thereof since the elution of metal ions derived from radical scavenging particles during fuel cell operation can be continuously prevented for a long time. The radical scavenger of the present invention comprises: radical scavenging particles; and a porous protective film on the surface of the radical scavenging particles, wherein the porous protective film comprises at least one material of high oxidative stability selected from the group consisting of silica, carbon nitride, heteroatom-doped graphene, a porphyrin-based compound, a phenazine-based compound, and derivatives thereof.

First claim

The invention claimed is:

1. A radical scavenger capable of removing hydroxyl radicals generated during an operation of a fuel cell, the radical scavenger comprising:
a radical-scavenging particle; and
a porous protective film over a surface of the radical-scavenging particle,
wherein the porous protective film comprises at least one material of high oxidative stability selected from the group consisting of silica, carbon nitride, heteroatom-doped graphene, a porphyrin-based compound, a phenazine-based compound and derivatives thereof,
wherein the heteroatom is selected from the group consisting of N, S, P, B and F,
wherein the radical-scavenging particle comprises Ce, a salt thereof, an oxide thereof, a nitride thereof, or a complex thereof,
wherein the porous protective film has a thickness of 0.5 to 50 nm, and
wherein an average pore diameter of the porous protective film is larger than 0.22 nm and smaller than 0.45 nm such that the porous protective film allows the hydroxyl radicals to pass therethrough but prevents Ce ions from passing therethrough.

2. The radical scavenger according to claim 1 , wherein the porous protective film comprises carbon nitride or a derivative thereof.

3. The radical scavenger according to claim 2 , wherein the porous protective film comprises graphitic carbon nitride or a derivative thereof, and
wherein the graphitic carbon nitride is g-C 3 N 4 or g-C 2 N.

4. A method for manufacturing a radical scavenger capable of removing hydroxyl radicals generated during an operation of a fuel cell, the method comprising:
forming a precursor layer comprising at least one precursor selected from the group consisting of a silica precursor and a carbon nitride precursor over a surface of a radical-scavenging particle; and
converting the precursor layer into a porous protective film,
wherein the radical-scavenging particle comprises Ce, a salt thereof, an oxide thereof, a nitride thereof, or a complex thereof,
wherein the porous protective film has a thickness of 0.5 to 50 nm, and
wherein an average pore diameter of the porous protective film is larger than 0.22 nm and smaller than 0.45 nm such that the porous protective film allows the hydroxyl radicals to pass therethrough but prevents Ce ions from passing therethrough.

5. The method according to claim 4 , wherein the precursor layer comprises at least one silica precursor selected from the group consisting of tetraethyl orthosilicate, tetramethoxysilane, (3-mercaptopropyl)triethoxysilane, and silicon tetrachloride.

6. The method according to claim 4 , wherein the precursor layer comprises at least one carbon nitride precursor selected from the group consisting of cyanamide, dicyandiamide, urea, melamine, polymelamine and a polymelamine-formaldehyde copolymer.

7. The method according to claim 6 , wherein the precursor layer comprises dicyandiamide.

8. The method according to claim 4 , wherein the forming the precursor layer comprises:
preparing a precursor solution comprising the at least one precursor selected from the group consisting of a silica precursor and a carbon nitride precursor;
applying the precursor solution to the surface of the radical-scavenging particle; and
removing a solvent from the precursor solution applied to the surface of the radical-scavenging particle.

9. The method according to claim 8 , wherein the precursor solution comprises at least one solvent selected from the group consisting of water, cyclohexane, hexane, dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and methylpyrrolidone.

10. The method according to claim 9 , wherein the applying comprises:
submerging the radical-scavenging particle in the precursor solution;
stirring the precursor solution containing the radical-scavenging particle; and then,
performing centrifugation.

11. The method according to claim 10 , wherein the removing the solvent comprises drying the precursor solution applied to the surface of the radical-scavenging particle.

12. The method according to claim 4 , wherein the converting the precursor layer into the porous protective layer comprises heat-treating the precursor layer.

13. A membrane-electrode assembly comprising:
an anode;
a cathode;
a polymer electrolyte membrane between the anode and the cathode; and
the radical scavengers according to claim 1 .

14. The membrane-electrode assembly according to claim 13 , wherein at least a portion of the radical scavengers are disposed (i) inside the anode at a surface of the anode facing the polymer electrolyte membrane, (ii) inside the cathode at a surface of the cathode facing the polymer electrolyte membrane, (iii) inside the polymer electrolyte membrane at a surface of the polymer electrolyte membrane facing the anode, (iv) inside the polymer electrolyte membrane at a surface of the polymer electrolyte membrane facing the cathode, (v) between the anode and the polymer electrolyte membrane, or (vi) between the cathode and the polymer electrolyte membrane.

15. The membrane-electrode assembly according to claim 14 , further comprising an interfacial bonding layer between the anode and the polymer electrolyte membrane, wherein the at least a portion of the radical scavengers are disposed in the interfacial bonding layer.

16. The membrane-electrode assembly according to claim 14 , further comprising an interfacial bonding layer between the cathode and the polymer electrolyte membrane, wherein the at least a portion of the radical scavengers are disposed in the interfacial bonding layer.

Assignees

• Kolon Inc
• Korea Advanced Inst Sci & Tech

Inventors

• Kim Hee-Tak
• Yuk Seongmin
• Lee Dong Wook
• Song Kah-Young
• Kim Jun Young

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/1004 Primary

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M4/8663 Primary

  Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers · CPC title

• H01M8/1053

  consisting of layers of polymers with at least one layer being ionically conductive · CPC title

• H01M8/1018

  Polymeric electrolyte materials · CPC title