A novel biomass modified brown coal as composite fuel for high performance direct carbon solid oxide fuel cells

Direct carbon solid oxide fuel cell (DC-SOFC) is a novel and efficient power generation device which utilizes solid carbon through electrochemical oxidation. Thereinto, clean and highly efficient utilization of coal is an important way to realize the “dual carbon” strategic goals. Nevertheless, the DC-SOFC performances with coal fuel are commonly low due to the certain amounts of inherent impurities of ashes and volatilizations. Taking this into account, a novel composite coal-based fuel is ingeniously designed as fuel for DC-SOFCs, in which the brown coal char is modified by adding a small proportion of kelp biomass carbon. With the configuration of Ag- Ce0.9Gd0.1O2-δ/YSZ/Ag-Ce0.9Gd0.1O2-δ symmetrical cell structure, the maximum power density of the cell with the novel composite fuel can reach 299 mW cm−2 at 850 ℃, which is outstandingly promoted compared to the cell with pure brown coal char (242 mW cm−2). Likewise, the composite fuel fed DC-SOFC presents a prolonged discharge stability than the kelp biochar fueled cell. This study introduces a novel concept of composite fuel for DC-SOFCs, which offers a new way for the development of high-performance direct brown coal fuel cells or direct carbon fuel cells with other coal fuel with the feature of highly efficient and clean use of coal for power generation.