CN108107090A - A kind of detection method of solid polymer electrolyte water electrolytic cell membrane electrode pollution - Google Patents

Abstract

The present invention relates to a kind of detection methods of solid polymer electrolyte water electrolytic cell membrane electrode pollution, are specially：Voltage detecting is carried out to electrolytic cell first under current-mode, observes the step of voltage；Then the electrochemical AC impedance performance of electrolytic cell is detected again, and by detecting the internal resistance of electrolytic cell, whether the incrementss for observing internal resistance apparent step occur, may determine that whether electrolytic cell performance degradation is caused by pollution by more than parameter.The detection method can be accurate and effective evaluation solid polymer electrolyte water electrolytic cell membrane electrode pollution condition.

Description

A detection method for membrane electrode contamination of solid polymer electrolyte water electrolysis cell

technical field

The invention relates to a detection method for producing hydrogen or oxygen by solid polymer electrolyte (SPE) water electrolysis, in particular to a detection method for membrane electrode contamination of a solid polymer electrolyte water electrolysis cell.

Background technique

Energy is an important material basis for developing the national economy and improving people's living standards, and it is also an important restrictive factor that directly affects economic development. With the society's emphasis on environmental protection, hydrogen energy, as a clean energy source, is about to replace gasoline, diesel, city gas, etc. and become the main energy source of life. At present, the mainstream technology for electrolytic hydrogen production is the lye electrolytic cell, but this technology has inevitable defects such as high pollution, low gas purity, high energy consumption, large volume, and alkali leakage of the electrolytic cell.

The solid polymer (SPE) hydrolysis electrolysis cell technology has many advantages such as high gas production purity, environmental protection, low energy consumption, small size and high gas production pressure, and can become the mainstream electrolytic hydrogen production technology replacing the lye electrolysis cell technology. However, the high-voltage environment in the process of water electrolysis can easily lead to oxidation and corrosion of materials such as bipolar plates or water supply pipelines. Pollutants such as metal ions produced by corrosion will contaminate the membrane electrode assembly, resulting in reduced catalyst activity, increased membrane resistance, and even membrane failure. Degradation affects the life of the electrolytic cell.

Therefore, it is necessary to provide an accurate method for detecting membrane electrode pollution, so that measures can be taken in time to effectively prolong the life of the SPE water electrolysis cell.

Contents of the invention

The invention provides an on-line detection to solve the pollution of the membrane electrode of the solid polymer electrolyte water electrolysis cell. The traditional detection of the pollution of the membrane electrode is mainly the offline analysis of the electrolysis cell, and the element of the membrane electrode section is analyzed by electronic probe analysis (EMPA). Detection is carried out to judge ion pollution. The invention provides an online detection membrane electrode pollution situation with convenient operation and low cost, which is used for judging whether the electrolytic cell needs to be treated or replaced.

Realize above-mentioned object technical scheme of the present invention is as follows:

A detection method for membrane electrode contamination of a solid polymer electrolyte water electrolysis cell, the detection method comprising the following steps:

1) Detect the voltage and current performance of the electrolytic cell:

Detecting the voltage of the electrolytic cell in a current mode with a density range of 0 to 300mA/cm ² , and observing the voltage step within the range;

2) Detect the electrochemical AC impedance performance of the electrolytic cell:

Check the ohmic resistance or/and charge transfer resistance of the electrolytic cell and observe a step in the increase in resistance.

Preferably, in the voltage detection in the step 1), the current density range is 0-200mA cm-2, and the membrane electrode is preliminarily determined to be polluted when the voltage step range is 0.1-0.8V.

Preferably, in the step 2), when the increase of ohmic resistance is 2 to 6 times of the initial value and the increase of charge transfer resistance is 1 to 7 times of the initial value, it can be determined that the membrane electrode is polluted.

Preferably, the ohmic resistance of the electrolytic cell is detected in the step (2).

Preferably, the membrane electrode includes an ion exchange membrane, a support layer located on one or both sides of the ion exchange membrane, and a catalyst layer formed by depositing a catalyst on the inner surface of the support layer.

Preferably, the support layer includes a nanoporous gold film; the nanoporous gold film has a three-dimensional connected pore structure, the pore diameter is 2nm-500nm, the porosity is 20%-70%, and the film thickness is 100nm-1000nm; the catalyst The loading amount of the catalyst is 5 μg/cm ² to 100 μg/cm ² , and the catalyst is distributed in an island shape or continuously on the inner surface of the support layer.

Preferably, the support layer is hot-pressed on the ion-exchange membrane in advance, then the catalyst is deposited, and finally the electrode is purified to obtain an ultra-thin film electrode.

Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects:

(1) The technical scheme provided by the present invention, by detecting the voltage, current and AC impedance characteristics of the electrolytic cell, carries out on-line detection to the membrane electrode of the solid polymer electrolyte water electrolytic cell, the method is simple, quick and easy to operate;

(2) The technical solution provided by the present invention is on-line detection, which can complete the detection of pollution without destroying the electrodes, reduces the consumption of expensive electrodes, and has low cost.

(3) The technical solution provided by the present invention can timely understand that the high-voltage environment in the water electrolysis process is likely to cause oxidation and corrosion of materials such as bipolar plates or water supply pipelines, so that metal ions and other pollutants produced by corrosion will pollute the membrane electrode assembly The disadvantages of the electrolytic cell are reduced, and the defects that lead to the decrease of the catalyst activity, the increase of the membrane resistance and even the degradation of the membrane, which affect the life of the electrolytic cell are overcome.

Description of drawings

Fig. 1 is the voltage and current detection curve that embodiment 1 detects;

Fig. 2 is the impedance curve before and after the membrane electrode pollution of embodiment 1 electrolytic cell;

Fig. 3 is the voltage and current detection curve that embodiment 2 detects;

Fig. 4 is the impedance curve before and after the membrane electrode pollution of embodiment 2 electrolytic cell;

Detailed ways

The experiment successively adopts the following two steps to judge the pollution of the electrolytic cell, as follows.

Example 1

As shown in Figure 1, the voltage and current performance of the electrolytic cell was tested in current mode. When the current density of the electrolytic cell increases from 0 to 350mA/cm ² , the voltage within this range has an obvious step, and the voltage rises rapidly from the initial 1.45V to 1.8V, and the voltage step is nearly 0.35V. Preliminary judgment This reduction in performance is caused by contamination.

As shown in Figure 2, the electrochemical AC impedance performance of the electrolytic cell was detected. By detecting the ohmic resistance and charge transfer resistance of the electrolytic cell, the ohmic resistance (R _Ω ) of the electrolytic cell increased from the initial 0.23Ωcm ² to 0.47Ωcm ² , while the charge transfer resistance (R _ct ) increased from the initial 0.12Ωcm ² to 0.35 Ωcm ² . , the increase in ohmic resistance is twice that of the initial one, and the increase in charge transfer resistance is three times that of the initial one, so it can be determined that the obvious step phenomenon in the membrane electrode is caused by pollution.

Example 2

As shown in Figure 3, the voltage and current performance of the electrolytic cell was tested in current mode. When the current density of the electrolytic cell is increased from 63mA/ ^cm2 to 95mA/ ^cm2 , the voltage within this range has a significant step, and the voltage rises rapidly from the initial 1.75V to 2.36V, and the voltage step is nearly 0.61V , it is preliminarily judged that this performance reduction is caused by pollution.

As shown in Figure 4, the electrochemical AC impedance performance of the electrolytic cell was detected. By detecting the ohmic resistance and charge transfer resistance of the electrolytic cell, the ohmic resistance (R _Ω ) of the electrolytic cell increased from the initial 0.47Ωcm ² to 0.65Ωcm ² , while the charge transfer resistance (Rct) increased from the initial 0.37Ωcm ² to 2Ωcm ² . , the increase of ohmic resistance is 1.6 times of the initial value, and the increase of charge transfer resistance is 5.4 times of the initial value, so it can be determined that the obvious step phenomenon in the membrane electrode is caused by pollution.

In summary, by testing the voltage and current performance and electrochemical AC impedance performance of the electrolytic cell, the membrane electrode pollution can be directly judged. The method of the present invention is easy to operate and low in cost, and can detect the membrane electrode pollution on-line, which can be timely It provides a basis for whether the electrolytic cell should be treated, and greatly prolongs the life of the electrolytic cell.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Those of ordinary skill in the art should understand that the specific implementation methods of the present invention can be modified or equivalently replaced with reference to the above embodiments, and these do not depart from the present invention. Any modifications or equivalent replacements in spirit and scope are within the protection scope of the pending claims.

Claims (7)

1. a kind of detection method of solid polymer electrolyte water electrolytic cell membrane electrode pollution, it is characterised in that：The detection Method includes the following steps：

1) the voltage and current performance of electrolytic cell is detected：

It is 0~300mA/cm in density range²Current-mode under, detect the voltage of the electrolytic cell, observation should in the range of voltage Step；

2) the electrochemical AC impedance performance of electrolytic cell is detected：

The Ohmic resistance or/and charge transfer resistance of electrolytic cell are detected, observes the step of resistance incrementss.

2. detection method described in accordance with the claim 1, it is characterised in that：The voltage detecting of the step 1), current density Scope is 0~200mA cm^-2, preliminary judgement membrane electrode is contaminated when voltage step scope is 0.1~0.8V.

3. detection method described in accordance with the claim 1, it is characterised in that：In the step 2), Ohmic resistance incrementss are Initial 2~6 times when charge transfer resistance incrementss are initial 1~7 times, can determine that membrane electrode is contaminated.

4. detection method described in accordance with the claim 1, it is characterised in that：Ohm electricity of detection electrolytic cell in the step (2) Resistance.

5. detection method described in accordance with the claim 1, it is characterised in that：The membrane electrode include amberplex, positioned at from The catalyst layer that deposited catalyst is formed on the supporting layer on the one or both sides surface of proton exchange and supporting layer inner surface.

6. according to the detection method described in claim 5, it is characterised in that：The supporting layer includes nanoporous gold thin film；Institute Stating nanoporous gold thin film has three-dimensional unicom pore structure, aperture 2nm~500nm, porosity 20%~70%, film thickness 100nm~1000nm；The loading of the catalyst is 5 μ g/cm²~100 μ g/cm², catalyst is in island in supporting layer inner surface Shape is continuously distributed.

7. according to the detection method described in claim 5, it is characterised in that：The supporting layer is warm in advance on amberplex After pressure, redeposited catalyst finally carries out purified treatment to electrode, obtains ultra-thin membrane electrode.