Metal-Supported solid oxide fuel cells (MS-SOFCs) tolerate rapid thermal cycling [1,2]. This makes them ideally suited for applications requiring rapid start-up time, or tolerance to thermal fluctuations arising from load-following or intermittent fuel flow. In direct flame mode, SOFCs are heated by a flame impinging on the anode side of the cell, and the flame also partially oxidizes the fuel to electrochemically- active species (such as hydrogen and carbon monoxide) [3–6].

In this work, we have developed a prototype consumer product by retrofitting MS-SOFCs to a commercial propane-fueled camping stove (Figure 1). The power produced by the fuel cells is conditioned by a simple microelectronic circuit to provide LED lighting and USB mobile phone charging.

Previous efforts [7] to systematically characterize the behavior of MS-SOFCs in direct-flame mode in carefully controlled lab environment will be summarized, including the impact of: air-to-fuel ratio in the flame, fuel flow velocity, burner-to-MS-SOFC distance, catalyst composition, and application of thermal insulation to the cell. The insight from these experiments was used in the present work to guide the design of a free-standing prototype, including cell size and stacking arrangement, and interaction with the stove flame and microelectronics. The prototype performance is shown in Figure 2. The MS-SOFC stack can be heated up from room temperature to delivery of useful power in less than 10 seconds. Operation points in LED mode and USB-charger mode fall on the overall operating curve of the MS-SOFC stack, and successful charging of smartphones is demonstrated.

[1] M.C. Tucker, Progress in metal-supported solid oxide fuel cells: A review, J. Power Sources. 195 (2010) 4570–4582. doi:10.1016/j.jpowsour.2010.02.035.

[2] J. Mougin, A. Brevet, J.-C. Grenier, R. Laucournet, P.-O. Larsson, D. Montinaro, L.M. Rodriguez-Martinez, M.A. Alvarez, M. Stange, L. Bonneau, E. Concettoni, L. Stroppa, Metal Supported Solid Oxide Fuel Cells: From Materials Development to Single Cell Performance and Durability Tests, ECS Trans. 57 (2013) 481–490. doi:10.1149/05701.0481ecst.

[3] M. Horiuchi, S. Suganuma, M. Watanabe, Electrochemical Power Generation Directly from Combustion Flame of Gases, Liquids, and Solids, J. Electrochem. Soc. 151 (2004) A1402. doi:10.1149/1.1778168.

[4] M.M. Hossain, J. Myung, R. Lan, M. Cassidy, I. Burns, S. Tao, J.T.S. Irvine, Study on Direct Flame Solid Oxide Fuel Cell Using Flat Burner and Ethylene Flame, ECS Trans. 68 (2015) 1989–1999. doi:10.1149/06801.1989ecst.

[5] M. Vogler, M. Horiuchi, W.G. Bessler, Modeling, simulation and optimization of a no-chamber solid oxide fuel cell operated with a flat-flame burner, J. Power Sources. 195 (2010) 7067–7077. doi:10.1016/j.jpowsour.2010.04.030.

[6] K. Wang, R.J. Milcarek, P. Zeng, J. Ahn, Flame-assisted fuel cells running methane, Int. J. Hydrogen Energy. 40 (2014) 4659–4665. doi:10.1016/j.ijhydene.2015.01.128.

[7] M.C. Tucker, A.S. Ying, Metal-Supported Solid Oxide Fuel Cells Operated in Direct-Flame Configuration, J. Power Sources. (2017).