GB/T 45092-2024Testing and evaluation of electrodes performance for hydrogen production by water electrolysis (English PDF)

1 Scope

GB/T 45092-2024 sets the methods for testing and evaluating the electrodes used in water electrolysis for hydrogen production. In an alkaline electrolyser the electrode is the component that decides both the energy cost of the hydrogen and the life of the stack, and China is installing electrolysers faster than anywhere else, increasingly coupled to wind and solar whose output swings - which is the condition under which coatings delaminate and reverse-current damage occurs. The standard describes the test and evaluation indicators and then the methods: the ultrasonic weight loss test for coating adhesion, the overpotential test, the positive and negative polarisation stability, the average cell voltage and its rate of change, and electrolysis under fluctuating current, each with its principle, reagents, equipment, samples, test conditions, test steps and data processing. It takes effect on 1 March 2025.

This document describes the test and evaluation methods for ultrasonic weight loss, overpotential, positive and negative polarization stability, average cell voltage, average cell voltage change rate, fluctuating current electrolysis of electrodes for hydrogen production by water electrolysis. This document is applicable to the performance test and evaluation of electrodes for hydrogen production by alkaline water electrolysis. The hydrogen evolution electrode and oxygen evolution electrode for hydrogen production by hydroxyl ion exchange membrane water electrolysis shall be implemented with reference to this document.

2 Normative references

The contents of the following documents constitute essential clauses of this document through normative references in the text. Among them, for dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB/T 678 Chemical reagent - Ethanol

GB/T 2306 Chemical reagent - Potassium hydroxide

GB/T 2900.98 Electrotechnical terminology - Electrochemistry

GB/T 3634.2 Hydrogen - Part 2: Pure hydrogen, high pure hydrogen and ultrapure hydrogen

GB/T 6682 Water for analytical laboratory use - Specification and test methods

GB/T 14599 Pure oxygen and high purity oxygen and ultra-pure oxygen

GB/T 15724 Laboratory glassware beaker

GB/T 21648 Industrial dense woven wire cloth

GB/T 28817 Single cell test methods for polymer electrolyte fuel cell (PEFC)

3 Terms and definitions

The terms and definitions defined in GB/T 2900.98, as well as the following terms and definitions, apply to this document.

3.1 Overpotential The absolute value of the difference between the working potential and the theoretical potential, when an electrode reaction occurs on the electrode.

Note: The overpotential must indicate the corresponding current density. The working potential and theoretical potential are values relative to the same reference system.

3.2 Average cell voltage The average cell voltage in a certain period of time when electrolysis is carried out at a certain current density.

Note: For a single-cell electrolyzer, the average cell voltage is the average electrolyzer voltage in a certain period of time; for a multi-cell electrolyzer, it is the value obtained by dividing the average electrolyzer voltage in a certain period of time by the number of cells in series.

3.3 Reversible hydrogen electrode When hydrogen is introduced into a solution of a certain pH and reaches saturation, the electrode where the redox reaction of hydrogen and hydrogen ions on the platinum electrode reaches equilibrium and which has a balanced electrode potential.

Note: The potential of the reversible hydrogen electrode is related to pH. The potential of the reversible hydrogen electrode at 25°C is E=-0.0592pH.

4 Test and evaluation indicators

See Table 1 for electrode performance test and evaluation requirements.

5 Ultrasonic weight loss test...

7 Positive and negative polarization stability test...

8 Test of average cell voltage and average cell voltage change rate...

Appendix A

(Normative) Electrode potential calibration of reference electrode A.1 Principle A three-electrode test system is used, with high-purity Pt sheets as test electrodes and counter electrodes; the electrode to be calibrated is used as the reference electrode. During the calibration process, hydrogen is introduced into the test solution to maintain it in a saturated state; then the multi-cycle cyclic voltammetry curve is tested at a rate of 1 mV/s. The value of the electrode to be calibrated is calculated based on the potential value of the zero current in the cyclic voltammetry curve. A.2 Calibration reagents, equipment, electrodes A.2.1 Reagents shall comply with the provisions of 6.2. A.2.2 Equipment shall comply with the provisions of 6.3. A.2.3 The electrodes used in calibration shall meet the following requirements:

a) The test electrode is a Pt electrode, which has a purity higher than 99.9%; the effective size of the electrode is 10 mm × 10 mm;

b) The reference electrode is the electrode to be calibrated, which is a mercury/mercury oxide electrode or a saturated calomel electrode with an external salt bridge;

c) The counter electrode is a Pt electrode, which has a purity higher than 99.9% and an effective size of 20 mm × 20 mm. A.3 Calibration steps The reference electrode calibration steps are as follows:

a) Power on and preheat: 10 minutes before starting the test, turn on the power of the electrochemical performance tester for preheating;

b) Inflation: Adjust the gas flow rate to 50 mL/min; fill the test solution with hydrogen until saturated. The hydrogen used shall meet the technical requirements of high-purity hydrogen in GB/T 3634.2;