Bo CHI

Symmetrical solid oxide cells (SSOCs) integrate the capabilities of solid oxide fuel cells and solid oxide electrolysis cells within a symmetric device, which have the advantage of simple fabrication and lower cost compared to conventional devices. Herein, to develop more advanced electrode materials to meet the catalytic activity for different electrode reactions, this study explores Sc-doped Sr0.9Fe0.8Sc0.1Co0.1O3−δ (SFSC) as an SSOC electrode material. Experiments show that Sc doping enhances the crystal stability of Sr0.9Fe0.9Co0.1O3−δ (SFC) in H2 and provides more oxygen vacancies for CO2 adsorption. Electrochemical tests reveal that the SFSC-Gd0.1Ce0.9O1.95 (GDC) electrode offers high power output, high CO2 electrolysis rates, and stability. Specifically, when operated as a fuel cell, the thus fabricated SSOC exhibits a peak power density of 781 mW·cm−2 and a polarization resistance of 0.117 Ω …

Developing excellent-performance cathode materials is an inevitable and challenging obstacle in the process of developing practical solid oxide fuel cells, especially in low temperature range. In this paper, we introduce barium into the premium SrCoO3-based cathodes and research its consequent effect in the oxygen reduction reaction process. It is observed that the barium dopant could expand the lattice, produce more oxygen vacancies and at some extent reduce the thermal expansion coefficient of parent perovskite, which results from the expanded free space for oxygen migration and weakened Co–O bond by Ba doping. The polarization resistances of single cells with Sr1-xBaxCo0.8Sc0.1Nb0.05Ti0.05O3-δ cathodes (x = 0, 0.2 and 0.5, defined as SCSNTi, SB0.2CSNTi and SB0.5CSNTi, correspondingly) are 0.038, 0.025 and 0.016 Ω cm2 at 600 °C, respectively, and corresponding peak power density of 0 …

Solid oxide fuel cell system is widely acknowledged as the leading alternative energy generation system in the field. Due to their high efficiency, low emissions, low noise, and various other advantages, solid oxide fuel cell systems are being considered for use in automobiles as a replacement for traditional internal combustion engines. However, prolonged operation and abnormal shutdowns can lead to performance degradation, which affects the efficiency, stability, and lifespan of stack. In the context of prolonged operation, considering the fluctuations in stack performance parameters and balance of plant, several regression models based on voltage parameters are established to accurately predict changes in stack performance. The results reveal that the genetic algorithm optimized backpropagation neural network model is highly sensitive in predicting the system performance degradation. Further analysis …

The increasingly serious environmental problems caused by the excessive development of fossil fuels necessitate the promoting of novel and effective energy technologies. As an environmentally friendly and effective promising solution in terms of its low emission, and fuel adaptability, the solid oxide fuel cell (SOFC) system has attracted widespread attention. To better promote the progress of SOFC, the SOFC testing system (SOFC TS) is very important. In this paper, we have established a dual preheating SOFC TS configuration where the fuel is first preheated by exhaust gas, and then preheated by the electric heater to the setting temperature. A comprehensive thermodynamic analysis is conducted to investigate the characteristic of this SOFC TS. Building upon this designed testing system, a multi-objective optimization approach is adopted to enhance the performance of the thermal management subsystem. The …

The increasing demand for green hydrogen and power production necessitates the development of novel and upgraded power generation technologies. The solid oxide fuel cell combined heat and power (SOFC–CHP) system is a promising solution due to its high efficiency, clean operation, and fuel flexibility. In practical terms, SOFCs can operate using a variety of fuels such as alcoholic fuel, hydrogen, ammonia, etc. Recently, methanol and ammonia have become noteworthy alternative fuel options as it possesses advantages such as low transportation cost and high hydrogen storage capacity. In this paper, we have established two SOFC–CHP models fueled by methanol or ammonia integrated with the steam Rankine cycle. A comprehensive thermodynamic model is proposed for energy and exergy analyses. Sensitivity analysis is performed to study the system's characteristics. The results show that the SOFC …

In the development of new electrochemical concepts for the fabrication of high-energy-density batteries, fluoride-ion batteries (FIBs) have emerged as one of the valid candidates for the next generation electrochemical energy storage technologies, showing the potential to match or even surpass the current lithium-ion batteries (LIBs) in terms of energy density, safety without dendritic grains, and elimination of dependence on scarce lithium and cobalt resources. However, the development of FIBs is still in its infancy and their performance is far from satisfactory, with issues such as the lower fluoride-ion conductivity of the electrolytes and the reversibility of the electrodes hindering their commercialization. Previous reviews have mainly focused on inorganic solid electrolytes with a brief emphasis on the development of various fluoride-ion conductors and their ion-conducting properties. Therefore, this review …

In this study, we developed an innovative strategy to fabricate highly active cathode and anode materials by acid etching perovskite oxide (ABO3) powder. (CoxFe1-x)3O4 nanoparticles were exsoluted in situ on an etched Pr0.2Sr0.8Co0.2Fe0.8O3-δ (P0.2SCF) catalyst to reconstruct heterojunctions in air. As a result, the exsolution of (CoxFe1-x)3O4 nanoparticles on the P0.2SCF surface led to the formation of perovskite-spinel interfaces in the cathode, and the generation of CoFe alloy and CoO nanoparticles embedded on the surface of the anode in 5 % H2. Two new composite catalysts modified with nanoparticles on the P0.2SCF skeleton were simultaneously prepared through the in situ exsolution of perovskite. At 850 °C, the polarization resistance values of the anode and cathode decreased by 37 % and 57 %, respectively. Furthermore, in a single cell with LSGM electrolyte and P0.2SCF-30-GDC symmetrical …

As a promising energy conversion device, solid oxide cell can realize efficient conversion between chemical energy and electrical energy under solid oxide fuel cell and solid oxide electrolysis cell mode. In this work, a Ruddlesden-Popper type oxide Pr1.5La0.5Ni0.8Cu0.2O4+δ (PLNC) with good mixed ionic-electronic conductivity is investigated as a dual functional air electrode for SOC. The results confirm that the peak power densities of the LSGM electrolyte supported cell with PLNC-GDC composite air electrode can reach 1.127, 0.911, 0.675 and 0.446 W cm−2 at 800, 750, 700 and 650 °C, respectively. Meanwhile, the cell possesses excellent durability for nearly 200 h under a constant current density of 400 mA cm−2 at 700 °C. The cell also shows superior electrolysis current density of 1.54 A cm−2 under electrolysis voltage of 1.3 V at 800 °C. The study demonstrates that PLNC is a promising dual functional …

The mass and heat transfer capability of the flow field greatly impact the performance of a solid oxide electrolysis cell (SOEC). In this study, rectangular and semicircular blockages are added to the flow channel to improve the heat and mass transfer process in the flow field. Additionally, the flow field synergy principle and the efficiency evaluation criterion (EEC) are used to evaluate the superiority of the flow field with additional blockages, respectively. The results show that the voltages of the flow channel with rectangular and semicircular blockages are reduced by 0.02 V and 0.015 V, respectively, at a current density of 10,000 A·m−2. Compared with semicircular blockages, the SOEC with rectangular blockages has a higher gas flow rate, lower thermal stress, and the EEC value increases by approximately 28 %. This indicates that the addition of the blockages can promotes the longitudinal gas flow for the improved …

Reversible protonic ceramic electrochemical cells (R-PCECs) are ideal, high-efficiency devices that are environmentally friendly and have a modular design. This paper studies BaFe0.6Zr0.1Y0.3O3−δ (BFZY3) as a cobalt-free perovskite oxygen electrode for high-performance R-PCECs where Y ions doping can increase the concentration of oxygen vacancies with a remarkable increase in catalytic performance. The cell with configuration of Ni-BZCYYb/BZCYYb/BFZY3 demonstrated promising performance in dual modes of fuel cells (FCs) and electrolysis cells (ECs) at 650 °C with low polarization resistance of 0.13 Ω cm2, peak power density of 546.59 mW/cm2 in FC mode, and current density of − 1.03 A/cm2 at 1.3 V in EC mode. The alternative operation between FC and EC modes for up to eight cycles with a total of 80 h suggests that the cell with BFZY3 is exceptionally stable and reversible over the long term …

To promote the electrocatalytic activity and stability of traditional La0.6Sr0.4Co0.2Fe0.8O3–δ (LSCF) oxygen electrodes in reversible solid oxide cells (RSOCs), conventional physical mixed method was used to prepare the Pd-LSCF composite oxygen electrode. The cell with Pd-LSCF|GDC|YSZ|Ni-YSZ configuration shows perfect electrochemical performance in both solid oxide fuel cell (SOFC) mode and solid oxide electrolysis cell (SOEC) mode. In the SOFC mode, the cell achieves a power density of 1.73 W/cm2 at 800 °C, higher than that of the LSCF oxygen electrode with 1.38 W/cm2. In the SOEC mode, the current density at 1.5 V is 1.67 A/cm2 at 800 °C under 50 vol% steam concentration. Moreover, the reversibility and stability of the RSOCs were tested during 192 h long-term reversible operation. The degradation rate of the cell is only 2.2%/100 h and 2.5%/100 h in the SOEC and the SOFC modes …

The oxygen sensors are extensively utilized in vehicles’ exhaust systems to monitor gases composition and control air-to-fuel ratio, thus reducing harmful emission and improving fuel economy. In equilibrium potentiometric sensors, the sealing performance is essential to ensure data accuracy. In this work, the 64SiO2–18TiO2–10Na2O–7K2O–1Al2O3 (wt%) glass was utilized as seals instead of traditional talcum in zirconium dioxide oxygen sensor. The interfacial compatibility with adjacent components (Fe–16Cr, Al2O3 and 8YSZ) and thermal cycle stability of seals were seriously evaluated in various ways. The equilibrium contact angles were lower 60° at high temperature, exhibiting better wettability and tight bonding at the interface. Besides, the leakage rates between glass and Fe–16Cr alloy were less than 0.01 sccm/cm at 650–800 °C and input gas pressures of 6.9–34.5 kPa. The oxygen sensor coupled with …

With the rapid development of novel energy conversion and storage technologies, there is a growing demand for enhanced performance in a wide range of electrocatalysts. Perovskite oxides (ABO3) have caused widespread concerns due to their excellent electrocatalytic properties, low cost, stable and reliable performance. In recent years, the research on anion O‐site doping of perovskite oxides has been a cynosure, which is considered as a promising route for enhancing performance. However, a systematic review summarizing the research progress of anion‐doped perovskite oxides is still lacking. Therefore, this review mainly introduces the elements and strategies of various common anions doped at O‐site of perovskite oxides, analyzes their influence on the physical and chemical properties of perovskites, and separately concludes their applications in electrocatalysis. This review will provide ideas and …

Perovskite oxides are widely used as electrodes in solid oxide electrolysis cell (SOEC) due to their good performance and structural stability. In the meantime, surface modification can promote adsorption and activation, which will significantly improve the catalytic activity of perovskite. Herein, an electro-reduction activation strategy is attempted to activate the electrochemical activity of A-site deficiency La 0.43 Ca 0.37 Ti 0.9 Ni 0.1 O 3-γ (LCTN) perovskite as fuel electrode of SOEC for CO 2 electrolysis. The results confirm that more adsorption and activation sites can be produced on the surface of LCTN after electro-reduction treatment. Under an electro-reduction voltage of 2.8 V in N 2, the polarization impedance of LCTN can be reduced from 0.859 to 0.208 Ω· cm 2 at 1.3 V and 800 C for CO 2 electrolysis. And the cell with LCTN fuel electrode shows stable long-term performance for CO 2 electrolysis with a current …

Hydrogen energy, the cleanest fuel, presents extensive applications in renewable energy technologies such as fuel cells. However, the transition process from carbon-based (fossil fuel) energy to desired hydrogen energy is usually hindered by inevitable scientific, technological, and economic obstacles, which mainly involves complex hydrocarbon reforming reactions. Hence, this paper provides a systematic and comprehensive analysis focusing on the hydrocarbon reforming mechanism. Accordingly, recent related studies are summarized to clarify the intrinsic difference among the reforming mechanism. Aiming to objectively assess the activated catalyst and deactivation mechanism, the rate-determining steps of reforming process have been emphasized, summarized, and analyzed. Specifically, the effect of metals and supports on individual reaction processes is discussed followed by the metal-support …

Liquid fuels like diesel, biodiesel, and alcohols can be utilized for onboard hydrogen production in auxiliary power systems by steam reforming, in which hydrogen productivity and carbon deposition are key issues. A-site deficient La1-xCr0.95Ru0.05O3 catalysts are prepared using the Glycine-nitrate method and characterized by multiple techniques. The catalyst with 20 % A-site deficiency exhibits about 95 % fuel conversion and stable performance over a 100 h continuous test at 750 °C and a steam/carbon ratio of 3.0 using n-hexadecane. However, the catalyst with a 10 % deficiency shows fluctuating fuel conversion with higher ethylene and ethane contents. Catalyst performance is mainly determined by active oxygen. The activation of steam on oxygen vacancies and Cr ions with variable valences could produce surface-free oxygen and freely migrating lattice oxygen respectively, which can react with CHx …

Lowering the operating temperature (450–650 °C) of solid oxide fuel cells (SOFCs) faces the intrinsic challenge of sluggish electrode reaction kinetics in the low temperature (LT) range. To accelerate the electrode reaction rate, many efforts have been put into the optimization of electrode composition and morphology. In this review, we have summarized recent developments of LT-SOFC electrodes, including anode and cathode materials. For anode performance improvement, the internal structure design, fine anode structure, reforming layer addition, and in situ exsolution techniques are introduced and their related functionalities are also explained, respectively. While for the cathode, we focus on the perovskite-type materials because of their superior catalytic performance and relatively good stability. The optimization of perovskite composition, including A site alkali or alkali-earth metal doping and B site variable …

The development of high-performance cathodes is crucial for intermediate temperature SOFCs. Thereinto, morphology regulation is an effective way to improve the electrocatalytic activity of SOFC cathodes. Nanofibers have been confirmed with the advantages of large specific surface area and high porosity over traditional nanoparticles, possessing a significant promotion effect on oxygen reduction reaction (ORR) activity. However, the traditional cell fabrication with high-temperature sintering will break the fiber structure and cause agglomeration. Herein, we adopted a sintering-free method to in-situ self-assemble La0.6Ca0.4Fe0.8Ni0.2O3-δ (LCaFN) nanofibers onto the YSZ electrolyte surface by polarization operation, which showed impressive performance compared to our previous work. After polarization for 21 h, the peak power density of the cell at 700 °C increased from 0.36 W·cm−2 to 0.60 W·cm−2, and the …

The application of cobalt-based perovskite cathode materials in proton-conducting SOFCs (H–SOFCs) is challenged by their high thermal expansion coefficient (TEC). To address interface degradation/separation between the cobalt-based perovskite cathode and the proton-conducting electrolyte, we design and prepare the high-entropy perovskite oxide (HEPO) BaCo0.2Zn0.2Ga0.2Zr0.2Y0.2O3-δ (BCX) as the cathode for proton-conducting SOFCs (H–SOFCs). BCX demonstrates remarkable performance and stability in the oxygen reduction reaction, validated through structural analysis and electrochemical characterizations. The TEC of BCX is as low as 12.75 × 10-6 K−1 compared to the 18.69 × 10-6 K−1 of the un-doped BaCoO3-δ (BC). The polarization resistance of BCX cathode about 0.69 Ω cm2 is realized at 600 °C, much lower than that for pristine BC cathode (1.27 Ω cm2). Cell with BCX cathode exhibits …

The pursuit of highly reactive cathodes promotes the improvement of the electrochemical performance of solid oxide fuel cells (SOFCs), while the side reaction between the cathode and the zirconia electrolyte produces a high-resistance phase impeding interfacial ionic transport. To address this issue, we designed an unsintered composite LaCo0.6Ni0.4O3−δ-Er0.4Bi1.6O3 (LCN-ESB) cathode via self-assembly onto a Y2O3-stabilized ZrO2 (YSZ) electrolyte under in situ current polarization to fabricate a porous cathode layer and a cathode/electrolyte interface with good contact. An area-specific resistance (ASR) of 0.205 Ω cm2 and a peak power density (PPD) of 0.788 W cm−2 can be achieved by a single cell with LCN-ESB cathode at 650 °C using hydrogen as fuel, and the cell runs stably for over 100 h without severe degradation. The oxygen reduction reaction (ORR) activity of the self-assembled LCN-ESB …