A Graphene Oxide Membrane Fuel Cell for Room Temperature Operation

Fuel cells for portable consumer electronics such as smartphones or optical head-mounted displays should be operated at relatively low temperatures for user comfort. However they are generally operated at over 80˚C. Recently our group reported the characterization of a graphene oxide membrane fuel cell (GOMFC) with a power density of 35 mW/cm² measured at 30°C, showing the potential of graphene oxide to be used as a fuel cell electrolyte at low temperature.¹

Graphene oxide (GO) is a sp²/sp³-hybridized carbon material with carboxyl, hydroxyl and epoxy oxygen functional groups on the surface and edges, which promote water uptake and make it insulating to electrons.² This is in contrast to graphene, which is highly electronically conductive and therefore suitable as e.g. a catalyst support.^3,4 GO is an excellent gas barrier and displays significant proton conduction,^5,6making it suitable as a fuel cell electrolyte.

Free-standing flexible GO membranes were prepared from GO dispersion in water by vacuum-filtration. These were characterized as a fuel cell electrolyte (Figure 1). GO was found to have improved gas barrier properties compared to Nafion, as well as higher tensile strength and water uptake. Despite the relatively low proton conductivity (around 1% that of Nafion), graphene oxide membrane fuel cells (GOMFCs) displayed reasonable power densities up to 35 mW/cm² at room temperature, approaching the performance of Nafion-based fuel cells at this temperature. By further reducing the thickness of the graphene oxide membrane and taking advantage of the high gas barrier properties an improved power density of up to 80 mW/cm²was achieved.

References:

1. T. Bayer, S. R. Bishop, M. Nishihara, K. Sasaki, and S. M. Lyth, J. Power Sources, 272, 239–247 (2014).

2. D. R. Dreyer, S. Park, C. W. Bielawski, and R. S. Ruoff, Chem. Soc. Rev., 39, 228–240 (2010).

3. L. Jianfeng, K. Sasaki, and S. M. Lyth, ECS Trans., 58, 1751–1762 (2013).

4. S. M. Lyth, L. Jianfeng, and K. Sasaki, ECS Trans., 58, 1529–1540 (2013).

5. R. R. Nair, H. A. Wu, P. N. Jayaram, I. V. Grigorieva, and A. K. Geim, Science, 335, 442–444 (2012).

6. K. Hatakeyama et al., Angew. Chemie, 53, 6997–7000 (2014).