Electrochemical oxidation of catalytic grown carbon fiber in a direct carbon fuel cell using Ce0.8Sm0.2O1.9-carbonate electrolyte

•Electrochemical performance of catalytic carbon fiber in a direct carbon fuel cell.•Existence of CO2 in cathode gas enhances the fuel cell output.•Direct carbon fuel cell anode oxidation suppresses CO formation.•An anode reaction scheme is proposed based on the results.

The electrochemical oxidation of catalytic grown carbon fiber has been examined in a direct carbon fuel cell (DCFC). The single cell contains a composite electrolyte layer made of a samarium doped ceria (SDC) and a eutectic carbonate phase. The cathode is a mixture of lithiated NiO and the composite electrolyte, while the anode is composed of NiO and SDC powder. Catalytic carbon fiber and the eutectic carbonate is premixed and used as the feed of the anode fuel. The effects of the cell pellet configuration, cathode gas composition and the operation temperature on the DCFC performance have been examined in this work. At 700 °C, the maximum power output achieves 112 mW cm−2 with a current density of 249 mA cm−2. The anode off-gas is analyzed with a gas chromatograph, and the Boudouard reaction is found suppressed by the electrical field in the fuel cell operation.

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