Electrolyte Fuel Cells Research Articles

An Investigation into the Potential Capabilities of a YSZ-SDCC Composite Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells

The development and analysis of Yttria-Stabilized Zirconia-Samarium-Doped Ceria Carbonate (YSZ-SDCC) composite electrolytes that are intended for use in Solid Oxide Fuel Cells (ITSOFC) at intermediate temperatures is the primary focus of this study, which represents a significant advancement in the technology of SOFC. When it comes to assessing the efficiency of fuel cells, which is a strategy that shows promise for the conversion of energy, the electrolyte material is one of the most significant components that must be considered. In this study, several different compositions of YSZ-SDCC composite electrolytes were investigated in detail. Electrochemical impedance spectroscopy, often known as EIS, was applied in order to carry out a thorough investigation into the conductivity and area-specific resistance (ASR) of these composite electrolytes. This

Oxygen Reduction Reaction Activity of Pt on Various Carbon Supports in OH- conducting Ionic Liquids

The intermediate temperature operation above 100 °C is one of important targets of next generation fuel cell development from both points of view of the activity enhancement and carbon monoxide poisoning mitigation of catalysts. To tackle this challenge, we have synthesized and applied OH- conducting ionic liquids as new fuel cell electrolytes, in which the progress of oxygen reduction reaction (ORR) has been successfully confirmed at temperatures above 100 °C under non-humid conditions. However, there is a problem to be solved that the overpotential for ORR is high due to the strong adsorption of ionic species on Pt catalyst. In this study, the electronic state of Pt catalyst was designed by applying heterogeneous atom-doped graphene materials as catalyst supports to reduce the ORR overpotential.A 1:1 mixture of tetrabutylphosphonium hydroxide (TBPOH) and tributylmethylphosphonium bis(trifluoromethanesulfonyl)imide (P4441TFSI) was prepared and used as OH- conducting ionic liquid. As Pt catalyst supports, reduced graphene oxide (RGO) and nitrogen-doped graphene (NG) were synthesized. The deposition of Pt catalyst on these graphene materials were carried out by a conventional reduction method of platinum chloride with ethylene glycol.The ORR activity of Pt catalysts supported on various carbon materials was evaluated by cyclic voltammetry in O2 saturated TBPOH/ P4441TFSI at 120 °C, and the positive shift of ORR onset potential from 0.4 V to 0.6 V and then 0.7 V vs. RHE was observed by changing the support from commercial Ketjen Black to RGO and then NG, accompanied by an increase in the ORR current density. X-ray photoelectron spectroscopy (XPS) revealed that this improvement is related to the different electronic state of Pt catalyst, and it was suggested that the supports with higher electron donating properties such as NG are suitable for Pt catalyst to enhance the ORR activity. Figure 1

Fabrication of Dense Electrolyte for Metal-Supported Solid Oxide Fuel Cells By Plasma Spray Method

Metal-supported SOFCs (MS-SOFCs) have attracted attention because of their potential for low cost and high mechanical robustness. However, the conventional cell fabrication process is not easily applied to MS-SOFCs. The difficulty of MS-SOFC fabrication is especially to form a dense electrolyte without oxidation and diffusion of the metal support. We’ve tried to use a plasma spray method to prepare the metal supported cells. Then, apparently dense electrolyte layer could be fabricated using doped lanthanum gallate instead of yttria stabilized zirconia. In this paper, electrochemical performance and gas tightness of the cells were evaluated to consider the applicability of plasma spray for MS-SOFC fabrication.A prepared MS-SOFC consists of porous metal substrate (SUS430), NiO-YSZ anode, Sr-, Mg-doped lanthanum gallate (LSGM9182), and conventional cathode (LSCF6428). The cell components, except for the porous substrate, were deposited by atmospheric pressure plasma spray (APS). Gas tightness of the cell was confirmed by open circuit voltage (OCV) measurement. Cell performance was evaluated by current-voltage measurement and impedance measurement. Post-analysis of the cell was conducted by SEM/EDS.The measured OCV was confirmed to be equivalent to theoretical value in humidified hydrogen at 973 K. It means the fully dense electrolyte layer could be prepared by plasma spray. Current density of I-V measurement was 0.6 Acm-2 at 0.5 V at 973 K. The impedance results showed larger over potential of anode reaction. This might be caused by anode electrochemical reaction and gas diffusion through anode and substrate layer. Further development of plasma spray anode is necessary for practical application; however, this study confirmed the possibility of the plasma spray method to fabricate the dense electrolyte for MS-SOFCs.This research was financially supported by NEDO.

A Review of Proton-Conducting Electrolytes for Efficient Low-Temperature Solid Oxide Fuel Cells: Progress, Challenges, and Perspectives

A Review of Proton-Conducting Electrolytes for Efficient Low-Temperature Solid Oxide Fuel Cells: Progress, Challenges, and Perspectives

Proton transfer driven by the fluctuation of water molecules in chitin film.

Proton-transfer mechanisms and hydration states were investigated in chitin films possessing the functionality of fuel-cell electrolytes. The absolute hydration number per chitin molecule (N) as a function of relative humidity (RH) was determined from the OH stretching bands of H2O molecules, and the proton conductivity was found to enhance above N = 2 (80%RH). The FIR spectrum at 500-900cm-1 for 20%RH (N < 1) together with first-principles calculations clearly shows that the w1 site has the same hydration strength as the w2 site. The molecular dynamics simulations for N = 2 demonstrate that H2O molecules with tiny fluctuations are localized on w1 and w2, and the hydrogen-bond (HB) network is formed via the CH2OH group of chitin molecules. Shrinkage of the O-O distance (dOO), which synchronizes with the barrier height, is required for proton transfer from H3O+ to adjacent CH2OH groups or H2O molecules. Nevertheless, dOO is hardly modulated for N = 2 because H2O molecules are strongly constrained on w1 and w2, and therefore, the transfer probability becomes small. For N = 3, novel HBs emerged between the additional H2O molecules broadly distributed on the w3 site and H2O molecules on w1 and w2. The transfer probability is enhanced because large fluctuations and diffusions in the whole H2O molecule yield large modulations of dOO. Consequently, long-range proton hopping is driven by the Zundel-type protonated hydrates in the water network.

Errata to "Benchmarking Power Generation From Multiple Wastewater Electrolytes in Microbial Fuel Cells With 3D Printed Disk-Electrodes".

Presents corrections to the paper, Benchmarking Power Generation From 2 Multiple Wastewater Electrolytes in Microbial 3 Fuel Cells With 3D Printed Disk-Electrodes.

Alternative Strategy for Development of Dielectric Calcium Copper Titanate-Based Electrolytes for Low-Temperature Solid Oxide Fuel Cells

HighlightsDielectric CaCu3Ti4O12 (CCTO) was used as electrolyte in low-temperature solid oxide fuel cells for the first time.A new heterostructure electrolyte was designed based on CCTO and Ni0.8Co0.15Al0.05LiO2−δ (NCAL). Promising ionic conductivity and high fuel cell performance were achievedCCTO–NCAL realized an electrolyte function due to its good dielectric property and a heterojunction effect.

High-Temperature Mechanical–Conductive Behaviors of Proton-Conducting Ceramic Electrolytes in Solid Oxide Fuel Cells

Proton-conducting solid oxide fuel cells (P-SOFCs) are widely studied for their lower working temperatures than oxygen-ion-conducting SOFCs (O-SOFCs). Due to the elevated preparation and operation temperatures varying from 500 °C to 1500 °C, high mechanical stresses can be developed in the electrolytes of SOFCs. The stresses will in turn impact the electrical conductivities, which is often omitted in current studies. In this work, the mechanical–conductive behaviors of Y-doped BaZrO3 (BZY) electrolytes for P-SOFCs under high temperatures are studied through molecular dynamics modeling. The Young’s moduli of BZY in fully hydrated and non-hydrated states are calculated with different Y-doping concentrations and at different temperatures. It is shown that Y doping, oxygen vacancies, and protonic point defects all lead to a decrease in the Young’s moduli of BZY at 773 K. The variations in the conductivities of BZY are then investigated by calculating the diffusion rates of protons in BZY at different triaxial, biaxial, and uniaxial strains from 673 K to 873 K. In all cases, the diffusion rate present a trend of first increasing and then decreasing from compression state to tension state. The variations in elementary affecting factors of proton diffusion, including hydroxide rotation, proton transfer, proton trapping, and proton distribution, are then analyzed in detail under different strains. It is concluded that the influences of strains on these factors collectively determine the changes in proton conductivity.

Sr-Yb Co-doping of BaCe0.4Zr0.6O3 Proton-Conducting Electrolyte for Solid Oxide Fuel Cells

Sr-Yb Co-doping of BaCe0.4Zr0.6O3 Proton-Conducting Electrolyte for Solid Oxide Fuel Cells

Synthesis and Physicochemical Characterization of Solid Oxide Electrolyte and Electrode Materials for Medium Temperature Fuel Cells

Finely dispersed СeO2–Nd2O3 and Gd2O3–La2O3–SrO–Ni(Co)2O3–δ mesoporous powders are synthesized by co-crystallization of the corresponding nitrates solutions with ultrasonic treatment and used to prepare nanoceramic materials with a fluorite-like, orthorhombic perovskite and tetragonal perovskite crystal structures respectively with CSR ~ 55–90 нм (1300ºC). The study of physicochemical properties of the obtained ceramic materials revealed an open porosity 7–11% for СeO2–Nd2O3 and 17–42% for Gd2O3–La2O3–SrO–Ni(Co)2O3–ä. Cerium oxide-based materials possess a predominantly ionic electrical conductivity with σ700ºС = 0.31 · 10–2 S/cm (ion transfer number ti = 0.71–0.89 in the temperature range 300–700°C) due to the formation of mobile oxygen vacancies at heterovalent substitution of Nd3+ for Се4+. Solid solutions based on lanthanum nickelate and cobaltite feature a mixed electronic-ionic conductivity with σ700°С = 0.59 ∙ 10–1 S/cm with the electron and ion transfer numbers te = 0.92–0.99 and ti = 0.08–0.01. The obtained ceramic materials are shown to be promising as solid oxide electrolyrtes and electrodes for medium temperature fuel cells.

A Comparative Effect of CsH2PO4/ZrP2O7 Composite Electrolytes for Intermediate Temperature Fuel Cell

Solid acid composite CsH2PO4 (CDP)/ZrP2O7 were synthesized and characterised with different weight ratio of CDP, SDP and ZrO2. The characterisations of the Solid acid composite were observed the structural, thermal stability and conductivity in terms of X-ray diffraction (XRD) analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis, Differential Thermal Analysis, and conductivity measurements. The amount of CDP and ZrP2O7 powder were used for pallet production. The composites powders were to form of pellets of 1mm thickness for conductivity measurement. ZrP2O7 in the composites has a large effect on the conductivity measurement and this material increased the temperature and time dependent conductivity of CDP by up to 4 orders of magnitude. The transition was identified in CDP/ZrP2O7 composites under atmospheric pressure. The thermal stability of the solid acid composites for dehydration, melting, and decomposition was investigated in the temperature range of 50 to 300 °C under environments with atmospheric humidification. Keywords: Composite Electrolytes, Conductivity, Thermal Analysis, Caesium Dihydrogen Phosphate, Pyrophosphates.

Synthesis and Physicochemical Characterization of Solid Oxide Electrolyte and Electrode Materials for Medium-Temperature Fuel Cells

Synthesis and Physicochemical Characterization of Solid Oxide Electrolyte and Electrode Materials for Medium-Temperature Fuel Cells

Oxygen transport mechanism and the effect of microstructure on the oxygen response behavior of an oxygen-sensitive composite Ce0.9Gd0.1O2-ẟ – La0.6Sr0.4FeO3-ẟ at high temperature

Compositions like gadolinium doped cerium oxide Ce0.9Gd0.1O2-ẟ and strontium doped lanthanum ferrite La0.6Sr0.4FeO3-ẟ, or their composites are well known in the field of fuel cell electrolyte, oxygen transporting membrane and catalytic reactor applications. This work offers insight into composite material's oxygen response characteristics, taking Ce0.9Gd0.1O2-ẟ and La0.6Sr0.4FeO3-ẟ in 70: 30 wt percent. One pot sol-gel method was employed for the powder synthesis. The powder was characterized by TG-DSC, XRD, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). FESEM-EDX and EDX-line profiling techniques were used to check the compositional homogeneity of sintered bodies. Oxygen response tests were conducted from ambient (20 % O2) to 100 % O2 concentration, using bulk samples sintered at three different temperatures, i.e., 1000, 1150, and 1250 °C at a fixed soaking time of 4 hours. The sintered specimens' apparent porosity, bulk density, surface morphology, and electrical conductivity were also examined. The sintering temperature significantly impacts response behavior as the porosity and grain size of the sintered body plays a vital role in sensing performance. The mechanism of response towards oxygen is also discussed. Sample 73–100 displayed the best performance among others. We achieved the lowest response and recovery time of 15 – 48 sec and 45 – 80 sec from a 0.60 mm thick bulk material at 950 °C. Harsh environments were intentionally created to check the reliability and reproducibility of the response data. This material could be a good candidate as an oxygen gas sensor at high temperatures owing to its good sensitivity, reliability, reversibility, and stability.

Two birds with one stone: Benefits of sintering additives on sinterability and electrical property of new protonic ceramic fuel cell electrolyte SrSn0.8Sc0.2O3-δ

Various approaches have been developed to address the challenges of difficult densification in traditional BaZrO3-based and BaCeO3-based protonic ceramic fuel cells (PCFCs) electrolytes. The addition of sintering additives, the most widely used approach, has been found to potentially compromise electrical performance while improving sinterability in traditional sintering. Recently, SrSn0.8Sc0.2O3-δ (SSS) has emerged as a promising proton-conductor material; however, there is still space for improvement in its electrical and sintering properties. In this study, a systematic investigation was conducted into the effect of sintering additives (NiO, ZnO, CuO) on the electrical performance of the new proton conductor SSS. Notably, SSS-1wt%NiO was found to decrease the sintering temperature from 1600 °C to 1400 °C (reaching 92 % relative density) and increase protonic conductivity from 2.61 × 10−3 S cm−1 to 3.06 × 10−3 S cm−1 at 600 °C, without any increase in electronic conductivity. This demonstrates a synergistic beneficial effect on both sinterability and electrical properties. Furthermore, the Ni-SSS|SSS-1wt%NiO|SSS-BCFZY single cell achieved the highest peak power density (528.5 mW cm−2 at 800 °C), surpassing all the other SSS-based single cells. Therefore, the addition of NiO to the SSS electrolyte demonstrates the significant sintering and electrical properties of SSS, proving evidence for the potential commercial application of SSS electrolytes for PCFCs.

Benchmarking Power Generation From Multiple Wastewater Electrolytes in Microbial Fuel Cells With 3D Printed Disk-Electrodes.

Microbial Fuel Cells (MFCs) have recently gained attention, as they are inexpensive, green in nature, and sustainable. As per the report, by Allied Market Research the global market size of MFCs will increase from $ 264.8 million in 2021 to $ 452.2 million in 2030, growing at a CAGR of 4.5%. The present work is a comparative study of various types of electrolytes that can be used in MFCs. The working electrodes were printed using conducting graphene-based Polylactic Acid (PLA) filaments with the help of a 3D printer under the principle of the fused deposition method. Simulated electrolytes and natural environmental microbial electrolytes were used here. Also, electrolytes of pure E. coli culture were studied. Lake water reported the highest power density of 8.259 mW/cm2 while Stale E. Coli reported the lowest around 0.184 mW/cm2. The study comprehensively lists potential wastewaters that can fuel the MFCs. With the pioneering of various comparative studies of electrolytes, one can insight into the recruitment of electrolytes with high-performance benchmarks for miniaturized energy storage and other microelectronics applications.

Effects of TiO2 on the mechanical and physical properties of Fe2O3-Doped Yttria-Stabilized Zirconia for electrolyte of Solid Oxide Fuel Cells

Yttria-Stabilized Zirconia (YSZ) based electrolytes of Solid Oxide Fuel Cell (SOFC) are widely used due to their higher ionic conductivity, stability, and availability. The present study focuses on improving the performance of YSZ-based electrolytes particularly by doping other particles into YSZ. TiO2 was doped into Fe2O3-8YSZ composite and the effects of TiO2 on the mechanical and physical properties of the composites were observed. The concentrations of TiO2 were varied by 0 wt%, 1 wt%, 3 wt%, and 5 wt% for different compositions of the composites. The samples were fabricated by the solid-state reaction method by pressing the powders at 250 MPa for 3 min and were sintered at 1250 °C for 4 h. The sintered samples were then undergone through characterization tests in terms of percentage of volume shrinkage, density, porosity, Diametral Tensile Strength (DTS), and microhardness. The highest values of volume shrinkage (34.83%), relative density (97.83%), DTS (36.58 MPa), hardness (965 HV), and the lowest porosity (2.17%) were found for 5 wt% TiO2 addition. Besides, the lowest values of volume shrinkage (28.44%), relative density (87.94%), DTS (3.24 MPa), microhardness (340 HV), and the highest porosity (12.06%) were found for Fe2O3-8YSZ composites without (0 wt%) TiO2 addition.

The characteristics of high temperature polymer fuel cell electrolyte membranes based on 2-pyridene polybenzimidazole blends with poly(vinyl-phosphonic acid)

The present study has focused on exploring new 2-pyridine-bridge-based polybenzimidazole (2-Py-PBIs) based materials for various energy-related uses in proton exchange membrane fuel cells (PEMFC). An electrochemical device, which transforms chemical energy into electrical energy, is known as fuel cell. Using solution polymerization with polyphosphoric acid as a solvent, a series of 2-Py-PBIs were synthesised from the 4,4'-([2,4′-bipyridine]-2′,6′-diyl)bis (benzene-1,2-diamine). 2-Pyridine bridge Polybenzimidazoles are cross-linked with poly (vinylphosphonic acid), which helps us to improve membrane properties like mechanical properties and proton conductivities. FT-IR was used to characterize chemical structure, Ubbelohde viscometer was employed to determine the inherent viscosity. Additionally investigated were the oxidative stability, swelling ratio, ion exchange capability, and water uptake for 2-Py-PBIs. Thermogravimetric analysis is used to evaluate thermal stability. The obtained 2-Py-PBIs membranes were thermally stable and mechanically strong when compared with conventional polybenzimidazole-based membranes. The 2-Py-PBIs:PVPA membranes showed proton conductivity between 0.10 µS/m to 4.65 µS/m.

Correction to: Preparation of Plasma Sprayed GDC Electrolytes for Metal-Supported Solid Oxide Fuel Cells

Correction to: Preparation of Plasma Sprayed GDC Electrolytes for Metal-Supported Solid Oxide Fuel Cells

Plasma-sprayed bulk-like yttria-stabilized zirconia coatings for solid oxide fuel cell electrolytes based on liquid-phase sintering-induced interfacial healing

To achieve a coating density meeting the solid oxide fuel cell (SOFC) electrolyte requirements of high gas tightness and ionic conductivity, in this study, a new interface healing densification process based on a liquid-phase sintering induction mechanism was conducted on plasma-sprayed 8 mol% Y2O3-stabilized ZrO2 (8YSZ) coatings. Using Fe2O3 and Bi2O3 as healing additives, metallurgical healing of unbound interfaces was achieved by impregnating the additives into the gap interfaces, followed by liquid-phase sintering at 1200 and 1050 °C. After healing, the YSZ coating exhibited a dense bulk-like microstructure with a significant reduction in the gas leakage rate by two orders of magnitude, and the oxygen ion conductivity of the coating was significantly increased. The YSZ coating healed with the Fe2O3 additive showed an oxygen ionic conductivity nearly one order of magnitude higher than that of the as-sprayed coating, reaching more than 80% of the value of the high-temperature-sintered YSZ bulk.

Preparation of Plasma Sprayed GDC Electrolytes for Metal-Supported Solid Oxide Fuel Cells

Preparation of Plasma Sprayed GDC Electrolytes for Metal-Supported Solid Oxide Fuel Cells