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(a) Plots of voltage and power density versus current density at 500–650°C. (b) Representative impedance spectra measured at 650°C and open circuits.
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Tremendous efforts to develop high-efficiency reduced-temperature (≤ 600°C) solid oxide fuel cells are motivated by their potentials for reduced materials cost, less engineering challenge, and better performance durability. A key obstacle to such fuel cells arises from sluggish oxygen reduction reaction kinetics on the cathodes. Here we reported th...
Citations
... The R p values of SSOFCs with LSNF9146 are 2.65, 1.38, 1, and 0.59 Ω cm 2 at 700, 750, 800, and 850 • C, respectively, significantly lower than the LNF46 electrode. Typically, they share the same R o , demonstrating the structure stability of SSZ support with electrodes; the slight difference could be attributed to the connecting wires in the testing setup as reported in previous research [35]. To further elaborate on the polarization process of SSOFCs, the EIS curves were analyzed by the distribution of relaxation time (DRT) method. ...
In this work, La1−xSrxNi0.4Fe0.6O3-δ (0 ≤ x ≤ 0.2) oxides were synthesized and employed as the identical electrode of direct methane symmetrical solid oxide fuel cell (SSOFC). In addition, the phase structure, redox stability, electrical conductivity, chemical compatibility, and thermal expansion of La1−xSrxNi0.4Fe0.6O3-δ oxides were evaluated. The La2NiO4 phase occurs when the amount of doped Sr rises to 0.2. The composition of La0.9Sr0.1Ni0.4Fe0.6O3-δ (LSNF9146) boasts the highest conductivity of 463 S cm−1 with lowest activation energy of 0.066 eV as well as a relatively large thermal expansion coefficient. After treatment in methane for 10 h, the LSNF9146 oxide exhibits 33% lower carbon deposition than the LaNi0.4Fe0.6O3-δ (LNF46) oxide. Moreover, the impregnated LSNF9146 electrode demonstrates lower polarization resistance in both air and methane atmospheres. SSOFCs with impregnated LSNF9146 and LNF46 identical composite electrodes have the maximum power densities of 233 and 170 mW cm−2 at 850 °C in methane, respectively. These results prove that LSNF9146 is a promising symmetrical electrode with high catalytic activity, good redox stability, and coking resistance to direct methane SSOFCs.
... Owing to high operating temperatures, it has to face some limitations like high costs, slow start-up time, high degradation rates etc. SOFC is exceptionally well suited for power plants to provide a continuous stream of energy to the industry as well as to a whole city [30]. Currently, the performance of SOFC is improving year after year, thanks to advances in technology to develop SOFC materials, for example, SOFC can now easily be operated at high temperatures, typically 500-1000 °C [31]. ...
Abstract: Activated carbon (AC) is an extremely porous carbonaceous adsorptive substance which has a rigid carbon matrix with high surface area and broad functional groups. The structure is connected by chemical bonds; arranged irregularly, generating a highly porous arrangement of corners, crevices, claps, and cracks between the carbon layers. Activated carbons are produced high-temperature and chemical activation of waste biomass. The pores in the lattice network of activated carbon permit the removal of impurities from gaseous and liquid medium through adsorption. At present, the COVID-19 disease is the prime concern around the whole world because of its exponential infections and death rate. There is no medicine for this virus, and protection is the only remedy to survive from this contagious disease. Using a face mask is one of the best methods to get rid of COVID-19. The mask combined with activated carbon can be beneficial for adsorbing and disinfecting the virus as it is the versatile adsorbent for the elimination of the organic, inorganic, and pathogenic contaminants.
... Owing to high operating temperatures, it has to face some limitations like high costs, slow start-up time, high degradation rates etc. SOFC is exceptionally well suited for power plants to provide a continuous stream of energy to the industry as well as to a whole city [30]. Currently, the performance of SOFC is improving year after year, thanks to advances in technology to develop SOFC materials, for example, SOFC can now easily be operated at high temperatures, typically 500-1000 °C [31]. ...
The new coronavirus (COVID-19) has started spreading all over the world. Every infected is fighting to recover a little and every health worker is fighting to save a single life in this pandemic. There is no place for patients to stay in the hospital, health workers are given all possible services to save their lives. In this situation, uninterrupted power system is needed, which can be supplied by solid oxide fuel cells (SOFCs). Therefore, solid oxide fuel cells (SOFCs) are becoming attractive day by day with competing environmentally friendly energy sources due to high energy efficiency, low emission rate and comparatively low operating cost. The purpose of this work is to investigate how copper-doped perovskite electrode materials impact the performance of solid oxide fuel cells (SOFCs) to overcome such crucial times successfully. Different synthesis process of Cu-based electrodes and analyzing electrochemical properties were investigated in this work. The evaluation was performed in terms of synthesis process, sintering temperature, lattice type and parameters, electrical conductivity, thermal expansion coefficients (TEC), polarization resistance, activation energy, and power density. In order to provide additional energy during this pandemic COVID-19, low-cost, highly performed, and durable materials are needed to make SOFC.
... Owing to high operating temperature, it has to face some hindrance like high costs, slow start-up time, high degradation rates, etc. The SOFC is especially well suited for power plants to provide a continuous stream of energy to industry as well as to a whole city [31]. ...
Recently, the development and fabrication of electrode component of the solid oxide fuel cell (SOFC) have gained a significant importance, especially after the advent of electrode supported SOFCs. The function of the electrode involves the facilitation of fuel gas diffusion, oxidation of the fuel, transport of electrons, and transport of the byproduct of the electrochemical reaction. Impressive progress has been made in the development of alternative electrode materials with mixed conducting properties and a few of the other composite cermets. During the operation of a SOFC, it is necessary to avoid carburization and sulfidation problems. The present review focuses on the various aspects pertaining to a potential electrode material, the double perovskite, as an anode and cathode in the SOFC. More than 150 SOFCs electrode compositions which had been investigated in the literature have been analyzed. An evaluation has been performed in terms of phase, structure, diffraction pattern, electrical conductivity, and power density. Various methods adopted to determine the quality of electrode component have been provided in detail. This review comprises the literature values to suggest possible direction for future research.
... The main function of an SOFC cathode is to provide active sites for the reduction of oxygen molecules and to transport oxygen ions from the cathode surface to the cathode/ electrolyte interface [12]. Aspects related to chemical stability, durability, and electrochemical properties should be considered before the selection of materials for SOFC cathodes [13]. ...
The effect of current collecting layer (CCL) and cathode functional layer (CFL) thicknesses on the catalytic activity of the La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.8Sm0.2O1.9 (LSCF-SDC) composite cathode was investigated by electrochemical impedance spectroscopy at 600 °C for 100 h. Results revealed that the charge transfer process associated with the incorporation of O²⁻ ions and the surface oxygen reduction reaction rate are dependent on CFL and CCL thicknesses, respectively. Area-specific resistance is dependent on CCL thickness in high-frequency arcs and on CFL thickness in low-frequency arcs. No significant change was observed in area-specific resistance value as the thickness of LSCF CCL decreased (25–5 μm) while the LSCF-SDC CFL thickness (5-25 μm) was gradually increased. However, the LSCF-SDC composite cathode (without CCL) showed poor catalytic activity toward the oxygen reduction reaction and had a high area-specific resistance value (3.31 Ω cm²). When LSCF CCL (5 μm) was used, the area-specific resistance value decreased by 16 times relative to the ASR of a sample without CCL. The field emission scanning electron microscopy results indicated that these cathodes exhibited a clear change in microstructure on the surface of the LSCF CCL after 100 h of thermal treatment in oxygen. The particle agglomeration and Sr surface segregation affected the surface catalytic activity toward oxygen reduction reaction at the LSCF CCL. As a result, the ASR value increased gradually in 100 h thermal treatment.
Graphical abstract
... For instance, it has been demonstrated through the reduction of La0.4Sr0.4Ni0.03Ti0.97O3−δ that the B-site NP growth was preferential on the defective surface facets (i.e., [110] ABO 4+ / 4 2 Oterminated facets), owing to its roughness and higher concentration of oxygen vacancies and A-site deficiencies [4]. Similarly, studies focused on the role of the oxide surface non-stoichiometry in the exsolution process revealed that a higher degree of deficiencies in the perovskite led to a more defective surface structure (A1− BO3−δ > A1− BO3 > ABO3+δ), consequently leading to a higher extent of exsolution and uniformity in surface distribution of NPs (A1− BO3−δ > A1− BO3 > ABO3+δ) [81]. ...
... Temperature-dependent performance of SOCs containing nanoengineered (a) anodes for hydrogen oxidation (green), and (b) nanoengineered cathodes for ORR (green) as compared to the microstructured electrodes (red). The data in (a) for nanoengineered anodes were extracted from [8,[104][105][106][107][108][109][110], while the data for microstructured anodes from [ work toward substantial breakthroughs in activity and structural stability of MIEC oxide-based systems should start by synthesizing these materials with high surface area and controlled composition and surface structure. In addition, a refined electrocatalyst design would require the development of new or enhanced synthetic methods, which lead to nanocatalysts with bridged properties from the different nanostructures discussed above-i.e., it would have flexibility in NP composition and distribution from deposited NP/oxide systems along with the outstanding close NP-support interactions provided by exsolution routes. ...
High temperature electrochemical energy conversion and storage technologies, such as solid oxide electrochemical cells (SOCs), have emerged as promising alternatives to mitigate environmental issues associated with combustion-based technologies. There has been increased interest for nanoengineering SOC electrodes to enhance their efficiency. A major drive is the necessity for improved electrode kinetics via optimization of electrocatalysts for different key reactions in these devices. In this perspective, we discuss the requirements for SOC electrodes and nanoengineering strategies employed to achieve flexibility in electrode materials. We focus on identifying ways in which these nanoengineered materials foster advancements in the SOC electrocatalytic activity, selectivity, and stability. We conclude by proposing approaches that would lead to more stable electrocatalytic nanostructures with high degree of control over the number and nature of active sites. These nanostructures would enable systematic kinetic studies that could provide an in depth understanding of the reaction mechanisms that govern performance, leading to valuable knowledge for designing optimal electrode materials.[Figure not available: see fulltext.]. © 2019, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
... Therefore, LSGM as an electrolyte material showing much higher con- ductivity than YSZ [7,11,12] and higher oxide-ion transport number than ceria under reducing atmosphere has been investigated as the scaffold material for an SOFC with nano- scale electrocatalysts for low-temperature operation [13]. With nickel impregnation into porous LSGM scaffold sup- porting a thin LSGM electrolyte, a power density higher than 1.2 W cm À2 has been achieved at 600 C [13,14], which is very promising as a low-temperature fuel cell. Ni(O) is also impregnated into a thin LSGM porous anode functional layer on a thick Sr 0.8 La 0.2 TiO 3-d porous support for power densities higher than 1.12 W cm À1 at 650 C [15,16]. ...
Eutrophication in lakes and rivers caused by the nitrogen (N) and phosphorus (P) is urgent since the accumulation of N and P can possibly cause the algal blooms and devastation to the water ecological system. The removal of N and P in the landscape water would be an efficient way to reduce the enrichment of nutrition before they reach the large water system. The N and P removal efficiency of PFS as well as the synergistic effect of natural rocks (four types of purple parent rock (J3p, J2s, T1f, and J3s)) as promoter was examined under laboratory conditions. The results indicated that TN and TP removal efficiency of the composite coagulant was significantly better than that of PFS or purple parent rock alone and J3p + PFS (combination of PFS and J3p purple parent rock) showed the best TN and TP removal efficiency. TN and TP removal efficiency of 53.53 and 86.48%, respectively, were achieved with coagulant dosage of 6 g L⁻¹ J3p and 30 mg L⁻¹ PFS, water temperature of 30 °C, and wastewater initial pH of 9. In addition, Fourier transformed infrared (FTIR) spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis (EDX), and the water quality index analysis revealed that the treatment of TN and TP by using J3p + PFS was taking advantage of the flocculation function of PFS and the adsorption function of PFS and J3p. In which, the flocculation mechanism was mainly charge neutralization; adsorption mechanism was mainly physical and chemical adsorption.
... Therefore, LSGM as an electrolyte material showing much higher conductivity than YSZ [7,11,12] and higher oxide-ion transport number than ceria under reducing atmosphere has been investigated as the scaffold material for an SOFC with nanoscale electrocatalysts for low-temperature operation [13]. With nickel impregnation into porous LSGM scaffold supporting a thin LSGM electrolyte, a power density higher than 1.2 W cm À2 has been achieved at 600 C [13,14], which is very promising as a low-temperature fuel cell. Ni(O) is also impregnated into a thin LSGM porous anode functional layer on a thick Sr 0.8 La 0.2 TiO 3-d porous support for power densities higher than 1.12 W cm À1 at 650 C [15,16]. ...
Development of low-temperature solid oxide fuel cells (SOFCs) is crucially important for their stable and continuous operation as a reliable power source. With Ni nanoparticles impregnated into the thick anode support, Sr– and Mg– doped LaGaO3 (LSGM) based electrolyte has been demonstrated to be adept at reducing the ohmic resistance for high performance at low temperatures (450–650 °C). In this study, 55-μm LSGM-electrolyte-based SOFCs are prepared via the impregnation for both cathode and anode, and high performance is obtained at low temperatures. The durability and reduction-oxidation (redox) stability are examined in terms of the calcination temperature of LSGM/Ni(O) anode that determines the thermal growth of NiO crystals and interfacial reaction between NiO and LSGM. We find that the cell with anode calcined at 1100 °C does contain larger NiO grains and more secondary phases, but it shows similar power density comparing to the one calcined at 800 °C. Both cells are stable at 650 °C and no damage on the electrolyte is found during the redox cycle, but the performance of the former is more sensitive to the redox cycle due to the high ohmic resistance arisen from the possible discontinuous connection between the large Ni grains.
... Nyquist plots often exhibit large deviations, such as asymmetric, depressed Warburg arc for transmissive diffusion [38][39][40] or an inclined capacitive rays for bounded diffusion [41][42][43][44][45][46][47]. The most common heuristic approach to describe such deviations is the constant phase element (CPE), ( ) ...
We develop a mathematical framework to analyze electrochemical impedance spectra in terms of a distribution of diffusion times (DDT) for a parallel array of random finite-length Warburg (diffusion) or Gerischer (reaction-diffusion) circuit elements. A robust DDT inversion method is presented based on Complex Nonlinear Least Squares (CNLS) regression with Tikhonov regularization and illustrated for three cases of nanostructured electrodes for energy conversion: (i) a carbon nanotube supercapacitor, (ii) a silicon nanowire Li-ion battery, and (iii) a porous-carbon vanadium flow battery. The results demonstrate the feasibility of non-destructive "impedance imaging" to infer microstructural statistics of random, heterogeneous materials.
... Also, the infiltrated electrode exhibits an improved matching in coefficient of thermal expansion (CTE) with the electrolyte in comparison with the electrode prepared by screen printing and sintering process [ [13]. Furthermore, SSC infiltrated LSGM cathode with a low R p of 0.021 U cm 2 at 650 C was reported by Han et al. [14]. ...
Here we report the electrochemical performance and long-term stability of La0.8Sr0.2CoO3−δ (LSC), La0.58Sr0.4Co0.2Fe0.8O3−δ (LSCF) and SmBa0.5Sr0.5Co2.0O5+δ (SBSC) infiltrated (ZrO2) 0.89(Sc2O3) 0.1(CeO2) 0.01 (SSZ) cathodes at low temperatures. At 700 °C, the initial polarization resistance of the infiltrated cathodes increased in following order: SBSC-SSZ (0.054 Ω cm2) <LSC-SSZ (0.084 Ω cm2) <LSCF-SSZ (0.140 Ω cm2). After the heat treatment at 620 °C (820–1400 h), the degradation rate of the polarization resistance of LSC-SSZ, LSCF-SSZ and SBSC-SSZ cathode was 179%, 53.9% and 93.1% kh−1, respectively, while that of the ohmic resistance was 10.6%, 8.86% and 40.9% kh−1, respectively. X-ray diffraction (XRD) and scanning electron microscope (SEM) observation showed that the degradation was mainly caused by the morphological change of the infiltrated particles while the solid reactions between the infiltrated materials and SSZ backbones were not observed.
