Hierarchical porous Ni-Ce0.8Sm0.2O2-δ anodes in solid oxide fuel cells

The porous structure of anodes is crucial to the performance of intermediate-temperature solid state fuel cells (IT-SOFCs). With the rapid development of high performance cathodes, the role of anodes needs to be considered again. A hierarchical porous Ni-Ce 0.8 Sm 0.2 O 2-δ (SDC) anode consisted of ∼200 nm width, and ∼800 nm and ∼10 μm diameter pores can be formed by reducing NiO, and burning of polymethyl methacrylate (PMMA) and starch pore-formers with a total load of 20 wt%, respectively. For single cells with Ni-SDC|SDC|Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ configuration, the peak power density (PPD) (0.26–1.73 W·cm −2 ) at 723–923 K is achieved with the addition of 10 wt% starch + 10 wt% PMMA, which is 136–52 % and 86-14 % higher than that without pore-formers and with 20 wt% starch, respectively. More importantly, it has a similar long-term stability of the cell without pore-formers. The comprehensive results suggest that the apparent improvement in PPDs is primarily attributed to the increased length of effective three-phase boundaries due to the formation of a percolation network of anodes, while also highlighting the significant influence of anode/electrolyte interface polarization on the electrochemical performance of IT-SOFCs.