In-situ catalytic gasification of kelp-derived biochar as a fuel for direct carbon solid oxide fuel cells

Highlights: • Kelp biomass is utilized as fuel for DC-SOFCs. • The kelp biochar fuel exhibits unique porous structure. • The DC-SOFC fuelled by kelp biochar reveals a maximum power density of 285 mW cm⁻². -- Abstract: Direct carbon solid oxide fuel cell (DC-SOFC) is a larruping type of fuel cell due to its all-solid-state structure, which can generate electricity from converting the chemical energy contained in solid carbon fuels directly into electrical energy. As the most abundant carbon storage base on earth, besides commercial carbon, coal or the common biomass carbon fuels, the exploitation of marine biomass as an alternative fuel for DC-SOFC is a very intriguing topic. In order to make efficient utilization of biomass carbon obtained from the ocean, a high performing direct carbon solid oxide fuel cell fuelled by kelp biochar is demonstrated. As comparison, the performances of DC-SOFCs with activated carbon and catalyst-loaded activated carbon fuels are also investigated. Thereinto, the best performance of 285 mW cm⁻² at 850 °C is achieved in a DC-SOFC using kelp biochar fuel with Ag-Gd_0.1Ce_0.9O_2-δ /YSZ/ Ag-Gd_0.1Ce_0.9O_2-δ configuration. This study will provide promising utilization of alternative biomass in DC-SOFCs and broaden their available carbon scope.