Manipulating Nb-doped SrFeO_(3−δ)with excellent performance for proton-conducting solid oxide fuel cells

Nb-doped SrFeO_(3−δ)(SFO)is used as a cathode in proton-conducting solid oxide fuel cells(H-SOFCs).First-principles calculations show that the SrFe0.9Nb0.1O_(3−δ)(SFNO)cathode has a lower energy barrier in the cathode reaction for H-SOFCs than the Nb-free SrFeO_(3−δ)cathode.Subsequent experimental studies show that Nb doping substantially enhances the performance of the SrFeO_(3−δ)cathode.Then,oxygen vacancies(VO)were introduced into SFNO using the microwave sintering method,further improving the performance of the SFNO cathode.The mechanism behind the performance improvement owing to VO was revealed using first-principles calculations,with further optimization of the SFNO cathode achieved by developing a suitable wet chemical synthesis route to prepare nanosized SFNO materials.This method significantly reduces the grain size of SFNO compared with the conventional solid-state reaction method,although the solid-state reaction method is generally used for preparing Nb-containing oxides.As a result of defect engineering and synthesis approaches,the SFNO cathode achieved an attractive fuel cell performance,attaining an output of 1764 mW·cm−2 at 700℃ and operating for more than 200 h.The manipulation of Nb-doped SrFeO_(3−δ)can be seen as a“one stone,two birds”strategy,enhancing cathode performance while retaining good stability,thus providing an interesting approach for constructing high-performance cathodes for H-SOFCs.

Nanostructuring the electronic conducting La_(0.8)Sr_(0.2)MnO_(3-δ) cathode for high-performance in proton-conducting solid oxide fuel cells below 600℃

Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells（SOFCs） due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La_（0.8）Sr_（0.2）MnO_（3-δ）（LSM） is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures.Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below600℃ with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped Ba ZrO_3（BZY） backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600 ℃. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures（above 700 ℃）.