In-Plane Adhesion Analysis of Fuel Cell (PEFC) Electrodes

Introduction

In polymer electrolyte fuel cells (PEFCs), platinum (Pt) supported on carbon is used as an electrocatalyst, and it has been pointed out that the in-plane distribution of Pt may be involved in reaction bias and degradation. It is therefore important to evaluate not only the amount of Pt deposited, but also its distribution. We evaluated the in-plane deposition of Pt on PEFC electrodes using X-ray fluorescence analysis, which enables nondestructive analysis of composition and deposition amount. 

Elemental analysis

• Analysis: Fuel cell
• Use: Quality assurance
• Analyzed materials: Pt as catalyst
• Analysis method: Standardless FP method

Figure 1: Sample and measurement coordinates 

Table 1: Analysis results for each coordinate [mg/cm²]

Table 2: Results of simple 10 repetition measurement
(Coordinates 5)

Conclusion

Point measurements were performed on a 13 mm square sheet coated with a Pt-supported carbon electrode for the 9 coordinates shown in Figure 1 under the conditions of 3 mm diameter and 60 seconds measurement time. Based on the obtained Pt Lα fluorescence intensity, the amount of Pt deposition was quantitatively evaluated by the standardless FP method. The analysis results shown in Table 1 confirm that the amount of Pt deposition tends to be higher in the upper left of the diagonal direction, indicating that there is a variation in the in-plane distribution. As shown in Table 2, the measurement was repeated 10 times under the same conditions at the position of coordinate 5, and the coefficient of variation was 0.4%, indicating extremely good reproducibility.

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