A semiconductor-ionic fuel cell (SIFC) is recognized as a promising technology and an alternative approach to reduce the operating temperature of solid oxide fuel cells. The development of alternative semiconductors substituting easily reduced transition metal oxide is a great challenge as high activity and durability should be satisfied simultaneously. In this study, the B-site Ni-doped La0.2Sr0.7Ti0.9Ni0.1O3-δ (LSTN) perovskite is synthesized and used as a potential semiconductor for SIFC. The in situ exsolution and A-site deficiency strategy enable the homogeneous decoration of Ni/NiO nanoparticles as reactive sites to improve the electrode reaction kinetics. It also supports the formation of basic ingredient of the Schottky junction to improve the charge separation efficiency. Furthermore, additional symmetric Ni0.8Co0.15Al0.05LiO2-δ (NCAL) electrocatalytic electrode layers significantly enhance the electrode reaction activity and cells' charge separation efficiency, as confirmed by the superior open circuit voltage of 1.13 V (close to Nernst's theoretical value) and peak power density of 650 mW cm-2 at 550 °C, where the latter is one order of magnitude higher than NCAL electrode-free SIFC. Additionally, a bulk heterojunction effect is proposed to illustrate the electron-blocking and ion-promoting processes of the semiconductor-ionic composite electrolyte in SIFCs, based on the energy band values of the applied materials. Overall, we found that the energy conversion efficiency of novel SIFC can be remarkably improved through in situ exsolution and intentional introduction of the catalytic functionality.
Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.
Solid electrolyte membrane-based reactors (SEMRs) can be operated at super high temperatures with distinct reaction kinetics, or at reduced temperatures (300-500 oC) for industrial-relevant energy applications (such as solid oxide...
The electrolyte in a solid oxide fuel cell (SOFC) should have high ionic conductivity to guarantee high fuel cell performance. This requires tuning of the electrolyte structure, which is often limited by poor electrolyte performance when the operating temperature. Here, we report ceria–semiconductor (Sm0.075Nd0.075Ce0.85O2−δ, SNDC)/insulator (i-Al2O3) heterostructure composite electrolyte which enhances ionic conductivity and improves fuel cell performance by the interfacial engineering. A maximum power density of 1312.5 mW·cm–2 and an ionic conductivity of 0.18 S·cm–1 at 550 °C were achieved. A small amount of an ultrawide band gap i-Al2O3 (molar ratio of 92SNDC-8Al2O3) effectively improved the ionic transport of the electrolyte by creating a potential energy barrier at the heterointerface. In addition, the n–i suppresses electron conduction and improves the ionic conduction, contributing to the outstanding electrochemical performance observed. The results demonstrate that the interfacial engineering of the electrolyte could be a simple and effective method to facilitate the fast transport of the ions in low-temperature SOFCs.
Proton conductivity plays a crucial role in the advancement of materials for proton ceramic fuel cells (PCFCs) and a variety of electrochemical devices. Traditional approaches to enhancing proton conductivity in perovskites have largely relied on doping strategies to induce structural oxygen vacancies. However, these methods have yet to overcome the challenges associated with achieving desired proton conductivity. Here, we introduce an approach wherein intermediate Li+ ions act as a bridge linked to Ca vacancies, fostering a mechanism for accelerated proton transport. Utilizing protonated Ca5(PO4)3OH-H(Li) as an electrolyte, we achieve a proton conductivity of 0.1 S cm−1 and a fuel cell performance of 661 mW cm−2 at an operational temperature of 550 °C for realizing low temperature PCFCs. This proton transport synergy overcomes traditional doping limitations, enabling the advancement of proton-conducting electrolytes and enhancing the efficiency of proton conducting electrolyte fuel cells, with implications in energy conversion and storage technologies. The proton conductivity is insufficient in current proton ceramic fuel cells and electrochemical devices. Here, Ca5(PO4)3OH-H(Li) electrolyte allows intermediate Li+ ions to bridge with Ca vacancies, resulting in high proton conductivity in low temperature proton ceramic fuel cells.
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