A compact and seal-less direct carbon solid oxide fuel cell stack stepping into practical application

The direct carbon solid oxide fuel cell is a potential technology that efficiently and cleanly converts the chemical energy of solid carbon into electricity. Its superiority of all-solid-state configuration and unique operating mechanism indicate that it has a good application prospect in high energy density portable or backup power supplys. It can also be used to convert coal into electrical power. Here, for the first time, we report a compact direct carbon solid oxide fuel cell stack with 12 cells fabricated on a single 10 × 10 cm electrolyte plate. The plate covers a container filled with solid carbon-rich fuel to form a stack. No sealant and pipelines are needed and the carbon-rich fuel can be reloaded. Both activated carbon and sawdust of bauhinia tree branch are used as the fuel. The output power of such a stack approaches more than 10 W at 800 °C. Using 15 g of 5 wt% Fe-loaded activated carbon as the fuel, a stack discharging at a constant current of 1.5 A outputs an energy of 29 Wh, correspongding to an energy desnity of carbon of ∼2000 Wh kg⁻¹. This work shows the feasibility of developing direct carbon solid oxide fuel cell into a compact electricity generator using readily available carbon-rich fuels. It also shows promise of using this technology in clean and efficient conversion of coal to electricity.