A high-performance direct carbon solid oxide fuel cell powered by barium-based catalyst-loaded biochar derived from sunflower seed shell

Abstract

Direct carbon solid oxide fuel cell (DC-SOFC) is one of the most attractive thesises for clean and efficient utilization of solid carbon to produce electricity. According to the operating principle, DC-SOFC performance is closely associated with the carbon sources and catalysts of the reverse Boudouard reaction. Here, we report a high-performance DC-SOFC powered by the biochar derived from sunflower seed shell (SSS) with barium-based catalyst loaded. The physicochemical properties of the SSS biochar are characterized and analyzed detailly. The electrolyte-supported symmetrical SOFC fueled with the SSS biochar gives an output of 216 mW cm−2 at 850 °C, indicating a great potential of the SSS biochar for DC-SOFCs. More importantly, the best output of 265 mW cm−2 and open circuit voltage of 1.03 V are obtained from DC-SOFC operated on 5 wt% barium-loaded SSS biochar, which is comparable to the output of 273 mW cm−2 from the hydrogen-fueled SOFC at 850 °C with the identical configuration. The superiorities of the SSS biochar and barium-based catalyst are also reflected in the operation stability and fuel utilization of DC-SOFCs. The discharge platforms are stable and the longest lifetime is up to 28.0 h under 50 mA with the fuel utilization of 31.3%, which is very excellent and competitive. This work provides a new idea for the effective utilization of the SSS biochar and other biomass for DC-SOFCs.