Multi-Layer Thin Film Coatings on Bipolar Metal Plates for PEMFC

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2016-02; no. 38; p. 2567
• Main Authors: Gath, Kerrie K., Ricketts, Mark, Yang, Jun, Xu, Chunchuan, Hirano, Shinichi
• Format: Journal Article
• Language: English
• Published: 01.09.2016
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2016-02/38/2567

The proton exchange membrane fuel cell (PEMFC) offers the potential for an efficient, and reliable power source for vehicles. The bipolar plates are a key component in the stack providing mechanical support, supplying reactant gases to both anode and cathode, removing the reaction products, and providing electrical and thermal conductivity. [1] Bipolar plate materials are broadly divided into metallic and carbon-based materials. Carbon-based plate materials do well mechanically; still fabrication is difficult and costly. As a result, metallic bipolar plates are becoming increasingly popular.[2] Metal bipolar plates have all the necessary properties (including high thermal and electrical conductivity, low gas permeability, high manufacturability, and relatively low cost materials); however, chemical instability due to the highly corrosive environment of the PEMFC leads to the formation of a passive surface oxide layer. Altering the surface by coating with a corrosion resistant material can be cost prohibitive when considering the amount of coating necessary to overcome the harsh conditions in a PEMFC, fabrication of the coating, and the number of plates in a stack. Less costly metals for coating, such as titanium, typically form an oxidative layer while non-corrosive metals can form pits where the underlying metal becomes exposed. Our multilayer technique combines both metal types for a corrosion resistant economical solution. [3] This design prevents oxide formation from percolating throughout the layered structure via thin films of non-corrosive layers alternated with thicker Ti layers. The specialized structure of multilayers of thin films (Au/Ti) allows the noncorrosive layer, the most costly, to be <1 nm while maintaining the viability and conductivity of the coating and the metal bipolar plate. [1] H. Tsuchiya and O. Kobayashi, “Mass production cost of PEM fuel cell by learning curve,” International Journal of Hydrogen Energy, 29 (2004) 985–990 [2] K. RoBerg and V. Trapp, “Graphite-based bipolar plates,” in Handbook of Fuel Cells Fundamentals, Technology and Applications, W. Vielstich, A. Lamm, and H. A. Gasteiger, Eds., JohnWiley & Sons (2003) 308–314 [3] S Wang, J. Peng, W. Lui, and J. Zhang, Performance of the Gold-plated Titanium Bipolar Plates for the Light Weight PEM fuel cells,” Journal of Power Sources 162 (2006) 486–491  SHAPE  \* MERGEFORMAT Figure 1. Multilayer design model. Figure 1