Development of Electrocatalysts for Anion Exchange Membrane Fuel Cells

Abstract
Recent development of chemically stable anion exchange membranes and ionomers resulted in substantial increase in research and development in the field of Anion Exchange Membrane Fuel Cells (AEMFCs) [1]. One of the advantages of AEMFC technology is the possibility to use completely platinum group metal-free (PGM-free) electrocatalysts for the cathode (Oxygen Reduction Reaction, ORR) and the anode (Hydrogen Oxidation Reaction, HOR) [2, 3]. High performance of Membrane Electrode Assemblies (MEAs) with PGM-free catalysts was achieved using M-N-C type of materials (M=Fe, Co or Ni) [4]. The cathodic electrocatalysts consisted of transition metal, nitrogen and carbon matrix can be prepared by several methods: treatment of carbons with transition metal in ammonia atmosphere, high temperature pyrolysis of Metal Organic Framework (MOF) compounds or through templating approach (Sacrificial Support Method, SSM) [5, 6]. In contrast to massive research in the ORR for AEMFCs, the development of PGM-free catalysts for HOR is still in the early stage, with majority of electrocatalysts tested in Rotating Disk Electrode (RDE) conditions. The only publications in open literature on integration of PGM-free anodic materials (nickel-based) are limited to NiW and NiMo supported on carbon blacks [7, 3]. In a present contribution the design, synthesis and scale-up of different Ni-based anodic materials for AEMFC application is reported. The electrocatalysts were synthesized by thermal reduction of nickel and second metal precursors on the surface of commercial and in house prepared carbon supports (in house carbon supports are denoted as Engineered Catalyst Supports, ECS). Several important synthetic parameters such as ratio between metals, type of carbon support, reduction temperature etc. were optimized in order to achieve the highest performance in fuel cell tests. As-obtained electrocatalytically active anodic materials were integrated into the catalyst layer by proprietary method practiced at EWII Fuel Cells [8]. The catalyst layer variations included different catalyst:ionomer ratio, loading of the Ni-based catalysts in the MEA and other parameters. Fuel cell tests performed at Pajarito Powder and EWII Fuel Cells revealed high performance of PGM-free materials similar to reported earlier (Figure 1) [3]. Figure 1. Fuel cell performance of MEA with NiCu/C anode using different loadings in catalyst layer. Conditions: A: NiCu/C, C: Pt/C, Tcell = 60°C, 100% RH, flow rates = 200 ccm, backpressure = 10 psig. The future directions on improvement of fuel cell performance will be discussed. Acknowledgements: Department of Energy, Hydrogen Oxidation Reaction in Alkaline Media, Control Number: 0966-1624, Award Number: DE-EE0006962 (PI A. Serov) and ARPA-E DE-AR0000688 (PI B. Zulevi). References. [1] A. Serov, I. V. Zenyuk, C. G. Arges, M. Chatenet "Hot topics in alkaline exchange membrane fuel cells" J. of Power Sources (2017) DOI: doi.org/10.1016/j.jpowsour.2017.09.068 [2] Md M. Hossen, K. Artyushkova, P. Atanassov, A. Serov "Synthesis and characterization of high performing Fe-NC catalyst for oxygen reduction reaction (ORR) in Alkaline Exchange Membrane Fuel Cells" J. Power Sources (2017) DOI: 10.1016/j.jpowsour.2017.08.036 [3] S. A. Kabir, K. Lemire, K. Artyushkova, A. Roy, M. Odgaard, D. Schlueter, A. Oshchepkov, A. Bonnefont, E. Savinova, D. Sabarirajan, P. Mandal, E. Crumlin, I. V. Zenyuk, P. Atanassov, A. Serov "Platinum Group Metal-free NiMo Hydrogen Oxidation Catalysts: High Performance and Durability in Alkaline Exchange Membrane Fuel Cells" J. Mater. Chem. A (2017) DOI: 10.1039/C7TA08718G [4] R. Janarthanana, A. Serov, S. Kishore Pilli, D. A. Gamarra, P. Atanassov, M. R. Hibbs, A. M. Herring "Direct Methanol Anion Exchange Membrane Fuel Cell with a Non-Platinum Group Metal Cathode based on Iron-Aminoantipyrine Catalyst", Electrochim. Acta 175 (2015) 202-208. [5] J. K. Dombrovskis, A. E. C. Palmqvis "Recent Progress in Synthesis, Characterization and Evaluation of Non-Precious Metal Catalysts for the Oxygen Reduction Reaction" Fuel Cells 16 (2016) 4–22. [6] A. Serov, M. J. Workman, K. Artyushkova, P. Atanassov, G. McCool, S. McKinney, H. Romero, B. Halevi, T. Stephenson "Highly stable precious metal-free cathode catalyst for fuel cell application", J. Power Sources 327 (2016) 557-564. [7] Q. Hu, G. Li, J. Pan, L. Tan, J. Lu, L. Zhuang "Alkaline polymer electrolyte fuel cell with Ni-based anode and Co-based cathode" Int. Journal of Hydrogen Energy 38 (2013) 16264-16268. [8] T. Reshetenko, M. Odgaard, D. Schlueter, A. Serov "Analysis of alkaline exchange membrane fuel cells performance at different operating conditions using DC and AC methods" J. of Power Sources (2017) DOI: /doi.org/10.1016/j.jpowsour.2017.11.030 Figure 1