1. Why is resistivity an important parameter in PEM electrolysis hydrogen production?
In the process of PEM electrolysis hydrogen production, platinum-coated titanium felt is used as anode diffusion layer material, and its resistivity is a key parameter that needs to be detected and controlled. The main reasons are as follows:
Affect electrolysis efficiency
If the resistivity of platinum-coated titanium felt is too high, it will increase the internal resistance of the electrolytic cell, reduce the electrolysis efficiency, and cause additional energy loss. Therefore, the resistivity of platinum-coated titanium felt needs to be controlled at a lower level to improve electrolysis efficiency.
01
Affect electrolysis voltage
The operating voltage of the electrolytic cell is proportional to the internal resistance. Excessively high resistivity of platinum-coated titanium felt will require higher electrolysis voltage and increase system energy consumption.
02
Affect electrode reaction kinetics
As the anode diffusion layer, the resistivity of platinum-coated titanium felt will affect the kinetic processes of the electrode reaction, such as electron transfer, gas diffusion, etc., thereby affecting the rate of the electrolysis reaction.
03
Evaluate coating quality
Testing the resistivity of platinum-coated titanium felt can indirectly evaluate the uniformity and integrity of the coating. Abnormal resistivity may mean that the plating is defective or uneven.
04
In summary, detecting and controlling the resistivity of platinum-coated titanium felt is beneficial to optimizing the efficiency of PEM electrolytic hydrogen production, reducing system energy consumption, and ensuring the performance of the anode diffusion layer.
2. What factors are related to the change in resistivity drop before and after platinum plating?
High conductivity of platinum
Platinum is a precious metal with extremely high electrical conductivity, much higher than that of titanium. After platinum is plated on the surface of titanium felt, the presence of the platinum layer greatly enhances the overall electron conductivity, thus reducing the resistivity.
Coating thickness
The thicker the platinum coating, the smoother the conductive path and the lower the resistivity.
Coating uniformity
The coating has good uniformity and can form a continuous conductive network to avoid the existence of high-resistance areas, thereby obtaining a lower overall resistivity. On the contrary, uneven coating will cause the resistivity to increase.
Substrate surface condition
The surface roughness and defects of the titanium felt substrate will affect the adhesion and uniformity of the coating, thereby affecting the final resistivity. The quality of surface preparation is an important factor.
Coating process parameters
Optimization of coating process parameters such as bath concentration, current density, and temperature can help obtain ideal coating quality and thereby reduce resistivity.
In general, the decrease in resistivity of platinum-coated titanium felt is mainly due to the high conductivity of platinum, and is closely related to many factors such as coating thickness, uniformity, matrix state, and process parameters.
3. The relationship between platinum plating thickness and resistivity drop value
1. There is a clear correlation between the coating thickness of platinum-coated titanium felt and its resistivity reduction value. Generally speaking, the thicker the coating, the greater the resistivity drop.
2. Studies have shown that for every 1 μm increase in platinum-plated layer thickness, the resistivity of platinum-plated titanium felt can be reduced by about 10%. This is because a thicker coating can form a more continuous and complete conductive network, providing a smoother conduction path for electrons, thus reducing the overall resistance.
3. However, the increase in coating thickness is also affected by some limiting factors, such as process methods, material consumption, and resistivity requirements. Therefore, in actual production, it is necessary to weigh various factors and select a reasonable coating thickness to obtain the ideal resistivity level.
4. In addition to the thickness of the coating, the uniformity of the coating, the surface state of the substrate, the concentration of the plating solution, the current density and other process parameters will also affect the resistivity of the platinum-coated titanium felt. Only by comprehensively considering all influencing factors can we reduce the resistivity to the greatest extent and improve the performance of platinum-coated titanium felt as an anode diffusion layer.
4. Our product data
Sample 1: Cutting fiber titanium felt (porosity 60%~70%, size 0.4*30*30mm), platinum coating thickness 0.3 microns, characterized as follows:
Resistivity value before platinum plating: 0.28 ohm·cm (Ω·cm)
Resistivity value after platinum plating: 0.24 ohm·cm (Ω·cm)
In conclusion:
Resistivity drop value = (average resistivity before plating - average resistivity after plating) / average resistivity before plating
Resistivity drop value = (0.28-0.24)/0.28 =14.3%
The resistivity decreased by 14.3% before and after platinum plating.
Sample 2, drawn fiber titanium felt (porosity 60%~70%, size 0.4*40*40mm), platinum coating thickness 0.5 micron, characterized as follows:
The resistivity test results are as follows:
Resistivity before platinum plating:
|
Project: Drawn titanium fiber felt Thk0.4mm*L40mm*W40mm (No.: BARE TI-1-1), porosity: 60%~70%, average resistivity test result: 0.464 ohm·cm (Ω·cm) |
||||||||
|
Thin wafer resistivity (thickness ≤ 4mm) |
||||||||
|
Sample identification |
Range (A) |
Current (mA) |
Average distance between probes (mm) |
Diameter (mm) |
Diameter correction factor |
Thickness(mm) |
thickness correction factor |
Probe spacing correction factor |
|
1 |
0.1 |
17.76 |
1 |
40 |
4.441 |
0.4 |
0.9997 |
1 |
|
Test Data |
||||||||
|
Points |
X(mm) |
Y(mm) |
Forward voltage (μV) |
Reverse voltage (μV) |
Resistivity mΩ.cm |
Conductivity(s/cm) |
Date |
Time |
|
1 |
0 |
0 |
39 |
48 |
0.44 |
2273 |
2024/6/12 |
9:04:15 |
|
2 |
0 |
-10 |
38 |
48 |
0.43 |
2326 |
2024/6/12 |
9:05:14 |
|
3 |
-10 |
0 |
36 |
45 |
0.41 |
2439 |
2024/6/12 |
9:06:52 |
|
4 |
0 |
10 |
41 |
51 |
0.46 |
2174 |
2024/6/12 |
9:07:22 |
|
5 |
10 |
0 |
47 |
57 |
0.52 |
1923 |
2024/6/12 |
9:08:25 |
|
6 |
0 |
-14 |
45 |
56 |
0.51 |
1961 |
2024/6/12 |
9:09:11 |
|
7 |
-14 |
0 |
49 |
59 |
0.54 |
1852 |
2024/6/12 |
9:09:48 |
|
8 |
-14 |
0 |
43 |
53 |
0.48 |
2083 |
2024/6/12 |
9:10:06 |
|
9 |
0 |
14 |
40 |
50 |
0.45 |
2222 |
2024/6/12 |
9:10:38 |
|
10 |
14 |
0 |
42 |
52 |
0.47 |
2128 |
2024/6/12 |
9:11:10 |
|
11 |
10 |
10 |
36 |
46 |
0.41 |
2439 |
2024/6/12 |
9:11:41 |
|
12 |
10 |
10 |
47 |
57 |
0.52 |
1923 |
2024/6/12 |
9:12:01 |
|
13 |
10 |
10 |
38 |
49 |
0.44 |
2273 |
2024/6/12 |
9:12:23 |
|
14 |
10 |
10 |
36 |
46 |
0.41 |
2439 |
2024/6/12 |
9:13:04 |
|
Analyze data (resistivity) |
||||||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
average percent change |
|||
|
0.54 |
0.41 |
0.464 |
31.71% |
27.37% |
||||
Resistance before platinum plating:
|
Thin sheet resistor |
||||||||
|
Sample identification |
Range (A) |
Current (mA) |
Average distance between probes (mm) |
Diameter (mm) |
Diameter correction factor |
Thickness(mm) |
thickness correction factor |
Probe spacing correction factor |
|
1 |
0.1 |
44.4 |
1 |
40 |
||||
|
Test Data |
||||||||
|
Points |
X(mm) |
Y(mm) |
Forward voltage (μV) |
Reverse voltage (μV) |
Square resistance mΩ/□ |
Conductivity(s/cm) |
Date |
Time |
|
1 |
0 |
0 |
115 |
126 |
12.1 |
2024/6/12 |
9:15:57 |
|
|
2 |
0 |
10 |
109 |
121 |
11.5 |
2024/6/12 |
9:17:25 |
|
|
3 |
-10 |
0 |
81 |
93 |
8.7 |
2024/6/12 |
9:18:30 |
|
|
4 |
0 |
-10 |
94 |
106 |
10 |
2024/6/12 |
9:18:56 |
|
|
5 |
10 |
0 |
129 |
141 |
13.5 |
2024/6/12 |
9:19:55 |
|
|
6 |
14 |
0 |
136 |
149 |
14.3 |
2024/6/12 |
9:20:52 |
|
|
7 |
0 |
14 |
107 |
120 |
11.4 |
2024/6/12 |
9:21:24 |
|
|
8 |
-14 |
0 |
114 |
126 |
12 |
2024/6/12 |
9:21:58 |
|
|
9 |
0 |
-14 |
108 |
120 |
11.4 |
2024/6/12 |
9:22:27 |
|
|
10 |
10 |
10 |
114 |
126 |
12 |
2024/6/12 |
9:23:09 |
|
|
11 |
10 |
10 |
123 |
135 |
12.9 |
2024/6/12 |
9:23:32 |
|
|
12 |
10 |
10 |
94 |
107 |
10.1 |
2024/6/12 |
9:24:13 |
|
|
13 |
10 |
10 |
93 |
106 |
10 |
2024/6/12 |
9:24:32 |
|
|
Analyze data (sheet resistance) |
||||||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|||
|
14.3 |
8.7 |
11.52 |
64.37% |
48.70% |
||||
Resistivity after platinum plating:
|
Project: Drawn titanium fiber felt Thk0.4mm*L40mm*W40mm (No.: TI-PT-1-1), porosity: 60%~70% Platinum plating thickness: 0.5μm Resistivity test result: 0.302 ohm·cm (Ω·cm) |
||||||||
|
Thin wafer resistivity (thickness ≤ 4mm) |
||||||||
|
Sample identification |
Range (A) |
Current (mA) |
Average distance between probes (mm) |
Diameter (mm) |
Diameter correction factor |
Thickness(mm) |
thickness correction factor |
Probe spacing correction factor |
|
1 |
0.1 |
17.76 |
1 |
40 |
4.441 |
0.4 |
0.9997 |
1 |
|
Test Data |
||||||||
|
Points |
X(mm) |
Y(mm) |
Forward voltage (μV) |
Reverse voltage (μV) |
Resistivity mΩ.cm |
Conductivity(s/cm) |
Date |
Time |
|
1 |
0 |
0 |
19 |
36 |
0.28 |
3571 |
2024/6/12 |
10:17:21 |
|
2 |
0 |
10 |
23 |
40 |
0.32 |
3125 |
2024/6/12 |
10:18:06 |
|
3 |
-10 |
0 |
20 |
37 |
0.29 |
3448 |
2024/6/12 |
10:18:31 |
|
4 |
0 |
-10 |
14 |
32 |
0.23 |
4348 |
2024/6/12 |
10:18:53 |
|
5 |
10 |
0 |
29 |
46 |
0.38 |
2632 |
2024/6/12 |
10:19:37 |
|
6 |
14 |
0 |
25 |
43 |
0.34 |
2941 |
2024/6/12 |
10:20:08 |
|
7 |
0 |
14 |
22 |
40 |
0.31 |
3226 |
2024/6/12 |
10:20:29 |
|
8 |
-14 |
0 |
16 |
33 |
0.25 |
4000 |
2024/6/12 |
10:20:56 |
|
9 |
0 |
-14 |
18 |
35 |
0.27 |
3704 |
2024/6/12 |
10:21:26 |
|
10 |
10 |
10 |
24 |
41 |
0.33 |
3030 |
2024/6/12 |
10:21:44 |
|
11 |
10 |
10 |
25 |
42 |
0.34 |
2941 |
2024/6/12 |
10:21:58 |
|
12 |
10 |
10 |
19 |
36 |
0.28 |
3571 |
2024/6/12 |
10:22:12 |
|
13 |
10 |
10 |
21 |
38 |
0.3 |
3333 |
2024/6/12 |
10:22:27 |
|
Analyze data (resistivity) |
||||||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
average percent change |
|||
|
0.38 |
0.23 |
0.302 |
65.22% |
49.18% |
||||
Resistance after platinum plating:
|
Thin sheet resistor |
||||||||
|
Sample identification |
Range (A) |
Current (mA) |
Average distance between probes (mm) |
Diameter (mm) |
Diameter correction factor |
Thickness(mm) |
thickness correction factor |
Probe spacing correction factor |
|
1 |
0.1 |
44.4 |
1 |
40 |
||||
|
Test Data |
||||||||
|
Points |
X(mm) |
Y(mm) |
Forward voltage (μV) |
Reverse voltage (μV) |
Square resistance mΩ/□ |
Conductivity(s/cm) |
Date |
Time |
|
1 |
0 |
0 |
65 |
83 |
7.4 |
2024/6/12 |
10:38:41 |
|
|
2 |
0 |
10 |
67 |
85 |
7.6 |
2024/6/12 |
10:39:12 |
|
|
3 |
-10 |
0 |
67 |
84 |
7.6 |
2024/6/12 |
10:39:32 |
|
|
4 |
0 |
-10 |
60 |
77 |
6.9 |
2024/6/12 |
10:39:57 |
|
|
5 |
10 |
0 |
81 |
98 |
9 |
2024/6/12 |
10:40:31 |
|
|
6 |
14 |
0 |
70 |
88 |
7.9 |
2024/6/12 |
10:41:12 |
|
|
7 |
0 |
14 |
64 |
82 |
7.3 |
2024/6/12 |
10:41:34 |
|
|
8 |
-14 |
0 |
54 |
71 |
6.3 |
2024/6/12 |
10:42:15 |
|
|
9 |
0 |
-14 |
65 |
83 |
7.4 |
2024/6/12 |
10:42:38 |
|
|
10 |
10 |
10 |
74 |
92 |
8.3 |
2024/6/12 |
10:42:57 |
|
|
11 |
10 |
10 |
72 |
89 |
8.1 |
2024/6/12 |
10:43:12 |
|
|
12 |
10 |
10 |
60 |
77 |
6.9 |
2024/6/12 |
10:43:28 |
|
|
13 |
10 |
10 |
63 |
80 |
7.2 |
2024/6/12 |
10:43:41 |
|
|
Analyze data (sheet resistance) |
||||||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|||
|
9 |
6.3 |
7.53 |
42.86% |
35.29% |
||||
In conclusion:
Resistivity drop value = (average resistivity before plating - average resistivity after plating) / average resistivity before plating
Resistivity drop value = (0.464-0.302)/0.464=34.9%
The resistivity decreased by 34.9% before and after platinum plating.
We also tested two other groups under the same conditions:
|
Analyze data (sheet resistance) |
|||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|
0.56 |
0.36 |
0.432 |
55.56% |
43.48% |
|
Sample: BARE TI-1-2 not platinum plated
|
Analyze data (sheet resistance) |
|||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|
0.41 |
0.23 |
0.304 |
78.26% |
56.25% |
|
Sample: TI-PT-1-2 platinum plated 0.5μm
Conclusion: The resistivity dropped by 29.6% before and after platinum plating.
|
Analyze data (sheet resistance) |
|||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|
0.52 |
0.35 |
0.434 |
48.57% |
39.08% |
|
Sample: BARE TI-1-3 not platinum plated
|
Analyze data (sheet resistance) |
|||||
|
maximum |
Minimum |
average |
Maximum percent change |
Radial unevenness |
Average percent change |
|
0.38 |
0.24 |
0.303 |
58.33% |
45.16% |
|
Sample: TI-PT-1-3 platinum plated 0.5μm
Conclusion: The resistivity dropped by 30.2% before and after platinum plating.
The resistivity of the platinum-coated titanium felt processed using our electroplating process conditions is reduced by 10%, and the platinum-plated thickness only needs to be increased by 0.2~0.3μm. In the future, we will continue to update our test results under different conditions, provide you with the most professional technical support, and cooperate with the research and development work of customers from all walks of life.
We are committed to improving the electroplating process and using more comprehensive test data to provide customers with more professional suggestions. We look forward to exploring future energy with you!
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