Electrode for electrochemical cells and composition thereof

Patent metadata

Field	Value
Publication number	US-10283780-B2
Application number	US-201515527357-A
Country	US
Kind code	B2
Filing date	Dec 17, 2015
Priority date	Dec 19, 2014
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

An electrode for use in an electrochemical cell, especially a zinc-bromine flow battery or a hydrogen/bromine flow battery, and methods for manufacturing and using the electrode is provided. The electrode has a metal substrate and a catalytic coating applied onto the substrate wherein the catalytic coating has a Ru-rich mixture of ruthenium and having 70-80 mol % Ru, 1-5 mol % Pt and 17-25 mol % Ir. The catalytic coating composition exhibits a surprisingly high voltage efficiency and operating lifetime despite its relatively low Ir/Ru and Pt/Ru ratios. The underlying metal substrate is for example a porous Ti layer or a layer with titanium suboxides Ti x O y .

First claim

The invention claimed is:

1. Electrode for use in electrochemical cells comprising:
a metal substrate; and
a catalytic coating comprising a mixture of noble metals or oxides thereof, wherein said mixture comprises 70-80% ruthenium, 17-25% iridium and 1-5% platinum in mole percentage referred to the elements.

2. The electrode according to claim 1 , wherein the loading of ruthenium, iridium and platinum is 5 to 30 g/m 2 referred to the sum of the elements.

3. The electrode according to claim 1 , wherein said metal substrate consists of a titanium material.

4. The electrode according to claim 3 further comprising an intermediate layer containing titanium material applied between said metal substrate and said catalytic coating.

5. The electrode according to claim 4 , wherein said titanium material comprises titanium suboxides according to the formula Ti x O y , wherein x is in the range of 2 to 10 and y is in the range of 3 to 19.

6. The electrode according to claim 1 , wherein said substrate has an average porosity of 40% to 60%.

7. Method for the production of an electrode according to claim 1 comprising the following sequential steps:
applying a precursor solution comprising a mixture of ruthenium, iridium and platinum compounds in one or more coats over said metal substrate;
drying said metal substrate after each coating at a temperature of 80° C. to 150° C.; and
thermally treating said dried metal substrate at a temperature of 350° C. to 600° C.

8. The method according to claim 7 , wherein the precursor solution is applied to said metal substrate in 3 to 8 coats.

9. Process for energy storage comprising the following steps:
circulating a zinc bromide solution within at least one electrochemical cell; and
performing the electrolysis of said solution within said electrochemical cell;
said electrochemical cell being equipped with at least one electrode comprising a metal substrate and a catalytic coating comprising a mixture of noble metals or oxides thereof, wherein said mixture comprises 60-85% ruthenium, 0-25% iridium and 1-15% platinum in mole percentage referred to the elements, wherein said electrode alternately evolves and reduces bromine.

10. The process according to claim 9 further comprising the execution of a periodic electric charge and discharge cycle on said electrochemical cell by means of an external electric circuit.

11. Flow battery comprising at least one electrode according to claim 1 .

12. Flow battery comprising at least one electrode which alternately evolves and reduces bromine comprising a metal substrate and a catalytic coating comprising a mixture of noble metals or oxides thereof, wherein said mixture comprises 60-85% ruthenium, 0-25% iridium and 1-15% platinum in mole percentage referred to the elements, wherein said flow battery is a zinc/bromine flow battery, a hydrogen/bromine flow battery or an organic redox species/bromine flow battery.

Assignees

• Industrie De Nora Spa

Inventors

• Allen Christopher J
• Abraham Sobha
• Hardee Kenneth L

Classifications

• C25B1/24

  Halogens or compounds thereof · CPC title

• H01M8/184 Primary

  Regeneration by electrochemical means · CPC title

• H01M8/20

  Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) · CPC title

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title

• H01M4/8657

  layered · CPC title