Disclosure of the internal mechanism during activating a proton exchange membrane fuel cell based on the three-step activation method. (11th January 2021)

• Record Type: Journal Article
• Authors: Hu, Mingruo; Zhao, Runxian; Pan, Ruixin; Cao, Guangyi
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 3(2021)
• Page Start: 3008
• Page End: 3021
• Publication Date: 2021-01-11
• Subjects: Proton exchange membrane fuel cell -- Activation -- Resistance -- Electrochemical surface area; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.04.280
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In our previous peer-reviewed article, a three-step method is put forward for increasing the efficiency of activating a newly-built membrane electrode assembly (MEA). By changing the activation temperatures of each step of the three-step method, the fuel cell performance can be greatly improved when compared with a normal one-step activation method. In this article, a deep understanding of the internal mechanism of this three-step method is conducted. Both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are tested after each I–V test round of a step. Two indexes, i.e., resistance reducing rate and effective current generation of catalyst (ECGC), are put forward. By integrating these two indexes, it clearly shows that the three-step activation method includes two effects, i.e., pore digging effect and pore swelling effect, which dominates in Step 1 and Step 2 separately. Finally, a pore forming mechanism model is put forward, which explains that the pore digging effect helps to form more three-phase reaction points and the pore swelling effect helps the three-phase points to become more effective. The same model also explains why the electrochemical surface area (ECSA) decreases during Step 1 and Step 2. Highlights: Pore digging effect in the catalyst layer is found in the activation method. Pore swelling effect in the catalyst layer is found in the activation method. ECSA decreases during the activation process. Pore forming mechanism model is put forward.