Clean and Sustainable Power to X to Power by Reversible Symmetrical Solid Oxide Cells with Highly Active Ferrite Perovskite Electrodes

Abstract

Reversible symmetrical solid oxide cell (RSSOC) exhibits considerable potential for direct power to X and X to power at low cost and enhanced reliability. The electrode with promising electrocatalytic activity is vital to promote its overall performance. Thus, this work explores the La 0.6 Ca 0.4 Fe 0.8 Co 0.2 O 3-δ (LCFC) perovskite oxide for RSSOC. The results demonstrate that the LCFC exhibits promising conductivity (203 S•cm −1 ) and thermal expansion coefficient (14.3 × 10 −6 K −1 ) as the air electrode. Moreover, the reduced LCFC (fuel electrode) with in situ exsolved Co−Fe alloy nanoparticles exhibits excellent CO 2 adsorption ability and sufficient oxygen vacancies. The performance of the LCFC electrode can be significantly enhanced with the good compatibility air electrode and highly active fuel electrode. The cell in the SOFC mode demonstrates outstanding peak power densities of 0.962 and 0.673 W•cm −2 operated with H 2 and CO at 800 °C, respectively, while in the SOEC mode, the current densities of 1.631 and 1.574 A•cm −2 can be obtained at 1.5 V with 50% H 2 O−50% H 2 and pure CO 2 , respectively. The cell also exhibits excellent short-term stability in both the SOFC and SOEC modes. All of the results confirm the feasibility of the LCFC material used for the implementation of RSSOC.

Highly Efficient and Stable Intermediate-Temperature Solid Oxide Fuel Cells Using PrCo0.5Ni0.5O3−δ Cathode

“…For L 0.5 P 0.5 CN, the peak power density is 1.04 W cm –2 at 850 °C, which is 29.25% smaller than that of PCN, and for L 0.25 P 0.75 CN, the peak power density is 1.18 W cm –2 , which is 19.73% smaller than that of PCN at the same temperature. PCN presents superior peak power density compared with other conventional cathode materials, such as PrBaFe 1.9 Ga 0.1 O 5 , La 0.6 Ca 0.4 Fe 0.8 Co 0.2 O 3 , and La 0.6 Ba 0.4 Ni 0.2 Fe 0.7 Ti 0.1 O 3 . Therefore, it can be clearly seen from the results that Pr doping plays a key role in improving the output power of fuel cells, and PCN displays an excellent power density.…”

“…The overall damping rate of L 0.5 P 0.5 CN is ∼0.092% h –1 after operation for 100 h. The performance of L 0.25 P 0.75 CN is attenuated at a rate of 0.019% h –1 . And for PCN, it is almost nonattenuating after 100 h working, proving that Pr 3+ doping can mitigate the adverse attenuation, and it is obvious that the long-term stability of PCN is better than that of other two studied cathode materials and other conventional cathodes, such as La 0.6 Ca 0.4 Fe 0.8 Co 0.2 O 3 and La 0.6 Ba 0.4 Ni 0.2 Fe 0.7 Ti 0.1 O 3. Therefore, the replacement La with Pr ion exhibits excellent electrochemical performance and stability.…”

“…The electrochemical performance of cathodes is closely related to ORR and long-term durability. − As a mixed ion and electron conductor (MIEC) material, ABO 3 perovskite has attracted great attention to serve as cathode for SOFC due to its outstanding electronic conductivity and effective ionic conductivity. − Among them, cobalt-based perovskite oxide materials present superior catalytic performance. , However, its shortcomings are high coefficients of thermal expansion relative to typical electrolytes and relatively poor long-term stability, which limits the development of this material. , Up to now, ion doping, wet impregnation, and in situ exsolution methods to adjust the cell performance have been widely investigated. − Because the ion doping method is relatively simple and easy to duplicate, the oxygen vacancy concentration can be easily introduced by different A-site and B-site doping so as to obtain different electrochemical properties. , …”

Revealing the detrimental CO2 reduction effect of La0.6Sr0.4FeO3-δ-derived heterostructure in solid oxide electrolysis cells

“…To date, perovskite materials with mixed ionic-electronic conducting properties, excellent resistance to carbon deposition, and good cycle stability have received constant attention as alternatives to Ni-cermet electrodes for CO 2 reduction in SOECs. 13 , 14 Representative materials such as La 0.2 Sr 0.8 TiO 3+δ (LST), 15 Sr 2 Fe 1.5 Mo 0.5 O 6-δ (SFM), 16 , 17 , 18 La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3-δ (LSCM), 19 , 20 and (La, Sr)FeO 3-δ (LSF) 21 , 22 have been well explored. Besides, many methods have been proposed to increase the catalytic activity, such as A-site, 20 , 23 B-site doping, 24 , 25 and anion element doping, 21 , 26 as well as cation deficiency projects.…”