Direct carbon solid oxide fuel cells powered by rice husk biochar

The inefficient application of fossil energy is one of the fundamental factors leading to global warming. Bioenergy is a renewable energy and also a carbon-neutral energy, with advantages of extensive sources, diverse products, and environmental friendliness. Direct carbon solid oxide fuel cell (DC-SOFC) is a novel high-efficient bioenergy technology, which is able to directly convert the chemical energy of biochar into power. A biochar derived from rice husk is applied to power an electrolyte-supported DC-SOFC. The maximum power density of the cell with pure rice husk biochar is 135 mW cm−2 at 850°C, which enhances to 214 mW cm−2 after using a Boudouard reaction catalyst. The microstructures, components and thermochemical parameters of the biochar are characterized and analyzed. The results show that the microstructure of the rice husk biochar is rough and porous. Na, K, Mg, Al, and other elements are found to present in the biochar. The physicochemical properties of the biochar and the enhanced electrical output of the DC-SOFCs are demonstrated and discussed in detail.