Metal-supported solid oxide fuel cells (MS-SOFC) with infiltrated catalysts on both anode and cathode side are operated in direct-flame configuration, with a propane flame impinging on the anode. Placing thermal insulation on the cathode dramatically increases cell temperature and performance. The optimum burner-to-cell gap height is a strong function of flame conditions. Cell performance at the optimum gap is determined within the region of stable non-coking conditions, with equivalence ratio from 1 to 1.9 and flow velocity from 100 to 300 cm s−1. In this region, performance is most strongly correlated to flow velocity and open circuit voltage. The highest peak power density achieved is 633 mW cm−2 at 833 °C, for equivalence ratio of 1.8 and flow velocity of 300 cm s−1. The cell starts to produce power within 10 s of being placed in the flame, and displays stable performance over 10 extremely rapid thermal cycles. The cell provides stable performance for >20 h of semi-continuous operation.

The authors regret that a technical mistake has been discovered, which impacts the current density and power density reported in this article. Briefly, the mistake was caused by catalyst solution leaking out of the intended 1 cm2 catalyzed area and depositing catalyst over the whole cell. As a result, the calculated current and power densities (total divided by the catalyzed area) were higher than reality because the measured current and power were dividing by the intended 1 cm2 instead of the actual area including the leakage, which was approximately 5 cm2. This issue is presented, analysed, and discussed in further detail in the supporting information of Reference [1]. Note that this issue does not impact other reported data, including OCV, flame and cell temperature, comparison of various operating conditions, durability, thermal cycling stability, and general trends and conclusions. The authors would like to apologise for any inconvenience caused.