A novel CuFe2O4 ink for the fabrication of low-temperature ceramic fuel cell cathodes through inkjet printing

Inkjet printing is a mask-free, contactless, and precise thin film and coating fabrication technique, which can tailor the electrode microstructure of solid oxide fuel cells to provide a larger surface area with more reaction sites. For the first time, printable and functional CuFe2O4 inks were developed by analyzing particle size, viscosity, surface tension, density, and thermal properties. Two inks, named Ink (1) and Ink (2), were formulated with different compositions. Ink (2), containing 20 wt% 1,5-pentandiol, exhibited smaller particle sizes (0.87 μm) and a lower activation loss compared to Ink (1). For further optimization, NLK-GDC porous electrolyte substrates were inkjet printed with 30, 40, 50, 100 and 200 layers of Ink (2), with estimated thicknesses of 4.2, 5.6, 7, 14, and 28 μm. The best performance was achieved with a 100-layer inkjet-printed symmetric cell, exhibiting an ASR of 9.91 Ω cm2. To enhance the rheological properties of Ink (2), cyclopentanone was added, resulting in Ink (2) - Samba, which had improved characteristics. Ink (2) - Samba possessed an average particle size (D50) of 0.68 μm and a Z number of 3.89. Finally, EIS analysis compared a 100-layer inkjet-printed symmetric cell with Ink (2) - Samba to a drop-cast cell with the same ink to evaluate how the fabrication technique influences cell performance. Inkjet printing demonstrated a hierarchical porous microstructure, increased reaction sites, and reduced ASR from 19.59 Ω cm2 to 5.99 Ω cm2. Additionally, SEM images confirmed that inkjet printing reduced the particle size distribution during deposition. These findings highlight the significant impact of manufacturing techniques on electrode quality and fuel cell electrochemical performance.Peer reviewe

High-performance supercapacitor electrode materials based on chemical co-precipitation synthesis of nickel oxide (NiO)/cobalt oxide (Co3O4)-intercalated graphene nanosheets binary nanocomposites

Graphene (Gr)/metal oxide nanocomposites, as advanced electrode materials, have drawn significant attention in supercapacitors due to their two components' synergistic cooperation, which compensates each other's drawbacks and hence perform better than their individual components. In this study, two graphene/metal oxide nanocomposites, Gr/NiO and Gr/Co3O4 binaries were separately synthesized by a co-precipitation method in which NiO or Co3O4 as interlayer spacers were inserted into the graphene structure. The as-synthesized electroactive materials were drop-cast on the as-grown Cu(OH)2 nanowire arrays/Cu substrates fabricated by drenching copper into a rich-alkaline solution. Three-electrode's electrochemical characterizations in 6 M KOH electrolyte showed that Gr/Co3O4 and Gr/NiO exhibit high capacitances of 342.6 and 652 F g−1 at the scan sweep of 5 mV s−1, and 278.5 and 667.58 F g−1 at the current density of 1 A g−1, respectively. In addition, the power density of 250 W kg−1 leads to the energy densities of23.17 and 9.7 Wh kg−1 for Gr/NiO and Gr/Co3O4, respectively. The Gr/NiO with the cyclic stability of 95% has a better electrochemical performance than Gr/Co3O4 (with the cyclic stability of 83%), implying more pseudocapacitance contribution of the NiO nanoparticles embedded within the graphene nanosheets and more efficient synergistic cooperation between these two components. Furthermore, full Gr/NiO/Cu(OH)2/Cu||Gr/NiO/Cu(OH)2/Cu and Gr/Co3O4/Cu(OH)2/Cu||Gr/Co3O4/Cu(OH)2/Cu symmetric cells in the organic electrolyte of 1 M TEA-BF4 in acetonitrile within the potential window of 2 V were also assembled and at 10 mV s−1, exhibited the highest specific capacitances of 32.67 and 24.86 F g−1, respectively.Peer reviewe

Development and characterization of highly stable electrode inks for low-temperature ceramic fuel cells

Funding Information: The authors are thankful to Academy of Finland (Grant No. 13329016 , 13322738 ) for the financial support. Dr. Asghar also thanks the Hubei Overseas Talent 100 program.Inkjet printing is a potential contactless and mask-free additive manufacturing approach for solid oxide fuel cells. Here, a highly stable cathode ink using La0.6Sr0.4Co0.2Fe0.8O3 was developed and characterized with particle size analysis, viscosity, surface tension, density, and thermal analysis. Both fresh and 6-months stored inks showed excellent jetability behavior with a Z number of 2.77 and 3.45, respectively. The ink was successfully inkjet-printed on a (LiNaK)2CO3-Gd:CeO2 porous electrolyte substrate to fabricate a symmetric cell. The electrochemical impedance spectroscopy measurements showed that at 550 °C the inkjet printing lowered the ohmic resistance to one-third (from 1.05 Ω cm2 to 0.37 Ω cm2) and the mass diffusion resistance by 4.25 times (from 6.09 Ω cm2 to 1.43 Ω cm2) as compared to drop-casted cell by creating a hierarchical porous structure and increasing reaction sites. Successful inkjet printing of the functional electrode material opens up a new avenue for the fabrication of the low-temperature ceramic fuel cells.Peer reviewe

A review on solid oxide fuel cell durability : Latest progress, mechanisms, and study tools

Funding Information: The authors are thankful to Academy of Finland (Grant No. 13329016, 13322738) for the financial support. Dr. Asghar also thanks the Hubei Overseas Talent 100 program. Funding Information: The authors are thankful to Academy of Finland (Grant No. 13329016 , 13322738 ) for the financial support. Dr. Asghar also thanks the Hubei Overseas Talent 100 program . Publisher Copyright: © 2022 The AuthorsThe commercial breakthrough of solid oxide fuel cells (SOFCs) is still hampered by degradation related issues. Most SOFCs that perform well do not possess good stability. To achieve a targeted degradation rate of 0.2%/1000 h important to a durable SOFC device, it is vital to identify the sources of degradation. So far, the longest stable performance was given by F1002-97, a short stack from Forschungszentrum Jülich GmbH, which reached 93,000 h of operation at 700 °C under 0.5 A cm−2 constant current density with a degradation rate of 0.5%/1000 h. In this review, we discuss the most detrimental degradation mechanisms for the core components of the SOFC, mainly poisoning, microstructural deformations, and strains. Electrochemical, chemical, and structural characterization tools for quantifying degradation mechanisms are also presented. The following section addresses the most recent progress in SOFC durability and the associated methods for analyzing degradation. These techniques include different doping techniques (including Mo, Nb, Co, Ce, Ta, Sn, etc.), surface modifications (e.g.infiltration, exsolution techniques, protective coatings), and interface engineering. Finally, the factors that inhibit the enhancement of SOFC durability are briefly discussed, such as inadequate knowledge of the degradation process and limitations in the material choices.Peer reviewe

Structural properties and supercapacitive performance evaluation of the nickel oxide/graphene/polypyrrole hybrid ternary nanocomposite in aqueous and organic electrolytes

Recently, hybrid supercapacitors have attracted tremendous attention as promising energy storage and conversion devices due to their excellent energy density and high power density. In the present work, a novel pioneering hybrid ternary nanocomposite of NiO/Gr/PPy was synthesized by a low-cost co-precipitation method, followed by heat treatment and in-situ chemical polymerization. The as-synthesized nanocomposite was drop-cast on a modified Cu current collector to enhance the supercapacitive performance and stability in the electrolyte. The results of electrochemical characterization in 6 M KOH revealed the high specific capacitance and energy density of 970.85 F g−1 and 33.71 Wh kg−1 at 1 A g−1, respectively. This can be attributed to the synergic effect and hybrid performance of NiO, Gr, and PPy. Moreover, a full symmetric cell was assembled by using this hybrid ternary nanocomposite and evaluated in TEA-BF4/AN. The results showed the high specific capacitance and energy density of 66.17 F g−1 and 36.76 Wh kg−1 within the 2 V potential window, respectively.Peer reviewe

Recent Progress in the Study of Thermal Properties and Tribological Behaviors of Hexagonal Boron Nitride-Reinforced Composites

Ever-increasing significance of composite materials with high thermal conductivity, low thermal expansion coefficient and high optical bandgap over the last decade, have proved their indispensable roles in a wide range of applications. Hexagonal boron nitride (h-BN), a layered material having a high thermal conductivity along the planes and the band gap of 5.9 eV, has always been a promising candidate to provide superior heat transfer with minimal phonon scattering through the system. Hence, extensive researches have been devoted to improving the thermal conductivity of different matrices by using h-BN fillers. Apart from that, lubrication property of h-BN has also been extensively researched, demonstrating the effectivity of this layered structure in reduction of friction coefficient, increasing wear resistance and cost-effectivity of the process. Herein, an in-depth discussion of thermal and tribological properties of the reinforced composite by h-BN will be provided, focusing on the recent progress and future trends.Peer reviewe