Physical Modeling of Catalyst Degradation in Low Temperature Fuel Cells: Platinum Oxidation, Dissolution, Particle Growth and Platinum Band Formation. Issue 1 (27th November 2019)

• Record Type: Journal Article
• Authors: Jahnke, Thomas; Futter, Georg A.; Baricci, Andrea; Rabissi, Claudio; Casalegno, Andrea
• Is Part Of: Journal of the Electrochemical Society. Volume 167:Issue 1(2020)
• Publication Date: 2019-11-27
• Subjects: Fuel Cells - PEM -- Catalyst degradation -- Physical modeling -- Polymer electrolyte membrane fuel cell; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0232001JES
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The loss of electrochemical active surface area (ECSA) at the cathode is one of the main causes of performance degradation in Polymer Electrolyte Membrane Fuel Cells (PEMFCs). In order to investigate the catalyst degradation and the influence of the operating conditions we develop a multiscale degradation model which includes the formation and reduction of platinum oxides, platinum dissolution, particle growth due to Ostwald ripening, platinum ion transport through the ionomer and platinum band formation in the membrane. This degradation model is coupled with a 2D PEMFC performance model and predictions regarding ion concentration, ECSA evolution and particle growth are validated with dedicated experiments and literature data. Degradation under several AST protocols and under steady state operation are compared and discussed. The importance of a spatially resolved catalyst degradation model is conveyed by the occurrence of a depletion zone in the catalyst layer close to the membrane due to the platinum migration into the membrane. By comparing the correlation between platinum mass loss in the catalyst layer and the ECSA loss we conclude that catalyst degradation under AST conditions with nitrogen is not representative for the degradation under normal operation.