Proton-conducting ceramic fuel cells (PCFCs) fueled directly by ammonia have demonstrated remarkable advantages as a promising clean energy technology. However, conventional nickel-based cermet anodes in direct ammonia PCFCs (DA-PCFCs) exhibit insufficient catalytic activity and poor thermal stability for ammonia decomposition, leading to suboptimal electrochemical performance and shortened operational lifetime. In this study, an efficient ammonia decomposition catalyst (Ce0.9Gd0.1)0.9Ni0.05Fe0.05O2-delta (CGNF) with in-situ exsolved FeNi3 nanoparticles is investigated as an advanced anode catalytic layer (ACL) in DA-PCFCs. The results show that DA-PCFCs with CGNF ACL show excellent peak power densities of 1.010 W & sdot;cm-2 and can operate over 140 h at 600 degrees C with negligible degradation. In-situ exsolved FeNi3 together with CGNF can efficiently promote ammonia decomposition thus improve the electrochemical performance and long-term stability of DA-PCFCs. This work presents a practical and effective anode catalytic layer design strategy for DA-PCFCs.

Manganese oxide cathodes are promising candidates for aqueous batteries owing to their high operating voltage and large capacity. However, they suffer from severe Mn3+ disproportionation and Mn2+ dissolution in acidic aqueous batteries, hindering their practical applications. Herein, we construct an in situ trifunctional (conductive, hydrophobic, self-adaptive) interphase using PDMS-DE@PANI (epoxypropoxypropyl-terminated polydimethylsiloxane@polyaniline) core-shell nanocapsules for encapsulating Mn2O3. The electrochemically driven release of the liquid PDMS-DE core, synergizing with the PANI shell, effectively suppresses Mn2+ dissolution while ensuring rapid electron/ion transfer. Consequently, the PD-Mn2O3 cathode delivers a record-high capacity of 340 mAh g-1 at 0.2 A g-1 and retains 201 mAh g-1 (92% capacity retention) after 800 cycles at 1 A g-1. Paired with a HATN anode, the full proton battery achieves an exceptional energy density of 140 Wh kg-1 with 80% capacity retention over 800 cycles. This dynamic interphase engineering provides a robust strategy for developing high-energy, ultrastable aqueous proton batteries.

Aqueous proton batteries (APBs) have emerged as a promising candidate for next-generation energy storage systems due to their intrinsic low cost, exceptional safety, and competitive power/energy density. However, the widely used MnO2 cathode in acidic electrolytes typically operates relying on a dissolution-deposition chemistry, inherently plagued by low manganese utilization efficiency and subpar practical energy density. Herein, we report a novel Mn-based cathode material-Mn2O3-for a proton battery, which demonstrates high redox potential and superior specific capacity. Nevertheless, as an Mn-based cathode material, Mn2O3 still suffers from dissolution and capacity decay in the long-term cycling process. To address this challenge, an in situ polymer-metal complex interphase engineering strategy was proposed to regulate the proton transfer kinetics and inhibit the dissolution of the Mn2O3 electrode. In this strategy, polyacrylonitrile (PAN) was employed as both the coating matrix and the adhesive while acting as a metal ligand after cyclization. Manganese triflate (Mn(OTf)2) was introduced to catalyze the pyrolysis of cyano groups and coordinate with the generated pyridine nitrogen, driving crosslinking reactions to stabilize the polymer network and optimize ion transport pathways. Consequently, the functional PAN-Mn2+ complex interphase (C-PMn) inhibits the transport and dissolution of Mn2+ ions, enhances H+ permeability, and improves the capacity, cycling stability, and coulombic efficiency of the Mn2O3 cathode. For the first time, we reveal that the Mn2O3 cathode stores energy through a proton insertion/extraction mechanism in H2SO4 electrolyte, holding promise for high-energy-density rocking-chair proton batteries. As-assembled diquinoxalino [2,3-a:2',3'-c] phenazine (HATN)//Mn2O3 proton full battery exhibits a specific capacity of 239 mA h g-1 at 0.2 A g-1 (based on the cathode), an average discharge voltage of about 1 V, a good cycling stability (82% capacity retention after 500 cycles) and an energy density of 115 Wh kg-1 (based on the total mass of cathode and anode). These findings offer a promising cathode material for proton batteries and a cost-effective approach to optimizing the cathode performance in acidic electrolytes, thereby paving the way for the development of a durable, high-energy proton battery.

Mullite-type SmMn2O5-delta exhibits low thermal expansion, but its conductivity and catalytic activity are insufficient for high-performance solid oxide fuel cell cathodes. In this work, Sm is partially substituted by Pr, modulating the conductivity and oxygen-vacancy concentration, to enhance the catalytic activity. At 800 degrees C, the optimal Sm0.5Pr0.5Mn2O5-delta demonstrates a threefold enhancement in electrical conductivity (0.234 S cm(-1)) and a 64% reduction in polarization resistance (0.33 Omega cm(2)) compared to the undoped sample. The Sm0.5Pr0.5Mn2O5-delta-based cell delivers a peak power density of 961 mW cm(-2) at 800 degrees C, with a degradation rate of similar to 6.96% kh(-1) over 450 h of operation. After 50 thermal cycles between 200 and 800 degrees C, the performance degrades by only 0.227%/cycle. These results demonstrate that Pr-doped SmMn2O5-delta significantly enhances electrical conductivity and oxygen reduction reaction catalytic activity while preserving the mullite framework, providing a promising cathode candidate for SOFC with high power output and excellent long-term stability.

In this study, a series of cobalt-free spinels Ni1+xMn2-xO4 (x = 0, 0.2, 0.4, 0.6) were prepared by the solid-liquid composite method. After preparing them into full-cell tests, it was found that Ni1.4Mn1.6O4 (NMO) exhibited the best performance when x = 0.4, and subsequent in-depth research was focused on NMO. NMO has good thermal expansion matching with the electrolyte layer below 700 degrees C, as well as excellent mixed ionic-electronic conductivity. When employed as a cathode material in an solid oxide fuel cell (SOFC), the cell achieves a discharge power density of 1150.25 mW cm- 2 at 800 degrees C. However, as the oxygen ion conduction rate decreases with decreasing temperature, the power densities at medium and low temperatures are significantly lower, with only 248.97 mW cm- 2 at 650 degrees C and 33.55 mW cm- 2 at 600 degrees C. The combination of NMO with the electrolyte material 8YSZ results in a significant increase in power density at 650 degrees C and 600 degrees C, achieving 330.21 mW cm- 2 and 157.81 mW cm- 2, respectively. An SOFC with NMO-YSZ64 as the cathode demonstrates excellent long-term stability, and the voltage degradation rate is less than 1 % after 110 hours of galvanostatic discharge at 650 degrees C and 200 mA cm- 2. SEM analysis reveals that the microstructure of the cell remains intact after prolonged discharge and has good adhesion at the cathode-electrolyte interface. These results suggest that Ni1.4Mn1.6O4 and its composite cathodes are highly promising cathode materials.

To tackle the pressing issue of nitrate (NO3-) pollution in wastewater and simultaneously convert it into ammonia (NH3), Cu nanocluster-modified Rhodium (Rh) single atoms anchored on N-doped carbon were synthesized via pyrolysis of a zeolitic imidazolate framework-8 (ZIF-8) precursor and applied to the electrochemical reduction of nitrate at a low concentration. Structural characterizations (X-ray powder diffractometer (XRD), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and X-ray photoelectron spectroscopy (XPS)) confirmed the coexistence of Rh single atoms and Cu nanoclusters as well as their strong electronic interactions. Mechanistic investigations revealed that Rh sites enhanced *H generation via water dissociation and promoted NO3- adsorption, thereby facilitating *H transfer and subsequent hydrogenation steps. As a result, the optimized Cu97.5Rh2.5/NC catalyst exhibited outstanding NO3-RR performance, with a Faradaic efficiency (FE) of 84.53%, an NH3 yield rate of 1252.22 μg·h-1 mgcat-1 at -1.0 V vs reversible hydrogen electrode (RHE), an NH3 selectivity of 89.13% at -1.0 V vs RHE, and a NO3- conversion rate of 93.34% at -1.1 V vs RHE. This work presents a rational design for atom-economical catalysts, enabling sustainable NH3 electrosynthesis from nitrate-laden wastewater and reducing effluent NO3--N to meet World Health Organization (WHO) drinking water standards.

The oxidation behaviors of bare and Cu-coated SUS441 ferritic stainless steel were systematically investigated in methanol-steam atmospheres at 650 degrees C and 750 degrees C, conditions relevant to the anode of direct methanol solid oxide fuel cells (SOFCs). The bare and Cu-coated (5, 10, and 15 mu m) SUS441 alloy were evaluated in terms of oxidation kinetics, microstructural evolution, and electrical performance over 1000 h. The results showed that bare SUS441 exhibited typical parabolic oxidation, forming a multi-layered oxide scale dominated by Cr2O3, MnCr2O4, and Fe3O4, leading to a substantial increase in area-specific resistance (ASR) beyond the practical threshold. In contrast, Cu-coated specimens demonstrated significantly reduced oxidation rates and superior electrical stability. Among the tested coatings, the 10 mu m layer exhibited the most favorable balance between protection and material economy, maintaining an ASR below 4.0 m Omega cm2 after 1000 h at 650 degrees C. The improved performance is attributed to the selective barrier effect of Cu against oxidizing species and its ability to hinder Cr outward diffusion, although agglomeration at 750 degrees C partially compromised surface coverage. Cross-sectional analysis revealed the formation of a composite oxide (Cr2O3-Fe3O4) beneath the Cu layer, indicating that oxidation was mitigated but not entirely suppressed. These findings demonstrate that Cu electroplating is an effective and scalable approach for extending interconnect durability in methanol-fueled SOFCs, particularly at moderate operating temperatures.

Thermal expansion matching is crucial for solid oxide fuel cell (SOFC) cathode design to prevent interfacial delamination or cracking. This work adopts thermal expansion coefficient (TEC) matching as the primary design principle to enable both structural stability and high catalytic activity. A Mn-based mullite-type cathode, SmMn2O5 (SMO), is developed, and composite electrodes with Gd0.1Ce0.9O1.95 (GDC) are fabricated. To reveal the structure-property relationships, TEC and electrochemical performance measurements are combined with in situ X-ray diffraction (XRD), Raman spectroscopy, and density functional theory (DFT) analysis. SMO exhibited a low TEC (8.12 × 10-6 K-1) due to anisotropic lattice expansion and phonon scattering confirmed by XRD and Raman. The SMO-GDC composite displayed extremely well-matched TECs with yttria-stabilized zirconia, with only 2.36% deviation across the operating range. Electrochemically, the composite cathode achieved 580.9 mW cm-2 with polarization resistance of 0.193 Ω cm2 and maintained stable operation for 300 h. DFT further revealed that GDC addition facilitated interfacial charge transfer and shortened Mn-Mn dimers, explaining the enhanced catalytic activity. This cathode material selection strategy, prioritizing TEC matching as the primary principle, provides a new insight into SOFC cathode development.

Conversion of biogas into syngas expands its application scope from fuel for power generation to industrial feedstock for the synthesis of value-added chemicals; however, it is restricted to the limited CH4 conversion due to the mismatch between CH4/CO2 feeding ratios of biogas and the stoichiometry of the CH4 dry reforming reaction. Herein, we proposed a novel calcium-looping biogas dry reforming process (CaL-BR) to supplement exogenous CO2 into biogas in situ by the introduction of a CaO-based carbon-carrying cycle. Using the facilely prepared composite material CaO-Ni/Al2O3_1 for CaL-BR at 750 degrees C, the CH4 conversion was over 65% and 16.4% higher than that of conventional biogas reforming, enabling the syngas yield to reach as high as 136.7 mmol/g. Importantly, the proposed process exhibited superior cyclic stability with a decay in the biogas reforming performance below 3% over 20 CaL-BR cycles under typical biogas CH4/CO2 feeding ratios, which was confirmed to be a consequence of the suppressed sintering of Ni particles and carbon deposition. The proposed CaL-BR process offered a promising option to make the best of the CH4 resource in biogas with the simultaneous capture and conversion of CO2.

Underground coal gasification (UCG) technology can directly convert coal resources to syngas underground, making it important for coal utilization. In this work, the power generation, CO2 electrolysis, and reversible operation of flat-tube solid oxide cells (SOCs) fueled with UCG syngas were studied. The factors affecting the performances of flat-tube solid oxide cells were investigated. Fueled with syngas (Swan Hills, Canada) at 750 degrees C, the flat-tube cell achieved a maximum power density of 329.4 mW cm-2 and a current density of 650.8 mA cm-2 at 1.4 V. 100-cycle (250 h) reversible operation of flat-tube SOCs running on syngas (Swan Hills) was accomplished. No carbon deposition on the surfaces of the cell fuel channels was detected. The syngas conversion in flat-tube cells was illuminated based on density functional theory calculations.

Flexible photovoltaics with a lightweight and adaptable nature that allows for deployment on curved surfaces and in building facades have always been a goal vigorously pursued by researchers in thin-film solar cell technology. The recent strides made in improving the sunlight-to-electricity conversion efficiency of kesterite Cu$_{2}$ZnSn(S, Se)$_{4}$ (CZTSSe) suggest it to be a perfect candidate. However, making use of rare Mo foil in CZTSSe solar cells causes severe problems in thermal expansion matching, uneven grain growth, and severe problems at the back contact of the devices. Herein, a strategy utilizing single-crystal graphene to modify the back interface of flexible CZTSSe solar cells is proposed. It will be shown that the insertion of graphene at the Mo foil/CZTSSe interface provides strong physical support for the subsequent deposition of the CZTSSe absorber layer, improving the adhesion between the absorber layer and the Mo foil substrate. Additionally, the graphene passivates the rough sites on the surface of the Mo foil, enhancing the chemical homogeneity of the substrate, and resulting in a more crystalline and homogeneous CZTSSe absorber layer on the Mo foil substrate. The detrimental reaction between Mo and CZTSSe has also been eliminated. Through an analysis of the electrical properties, it is found that the introduction of graphene at the back interface promotes the formation of a quasi-ohmic contact at the back contact, decreasing the back contact barrier of the solar cell, and leading to efficient collection of charges at the back interface. This investigation demonstrates that solution-based CZTSSe photovoltaic devices could form the basis of cheap and flexible solar cells.

One critical factor contributing to the performance degradation of solid oxide fuel cells (SOFCs) is the Ni migration in the anode. In this work, we studied and compared the influence of H2O and CO2 concentrations in the fuel gas on Ni migration using patterned anode button cells. Scanning electron microscopy (SEM) images revealed the Ni migration emerged after 24 h of constant current discharge in fuel atmospheres containing H2O and CO2. As the H2O content in the fuel increased, the rate of Ni migration increased, indicating that H2O promoted Ni migration at the anode side and contributed to the performance degradation. CO2 improved Ni migration, and the effects of H2O and CO2 on Ni migration were equivalent. Moreover, the mechanism of SOFC anode Ni migration induced by CO2 in the fuel was discussed.

This study presents the design, fabrication, and evaluation of a high-performance flat-tube solid oxide cell (FTSOC) stack, which demonstrates exceptional power generation and hydrogen production capabilities. Comprising three large-sized FT-SOCs, each with an active area of 60 cm2, the stack was tested at 750 degrees C. It achieved a peak power density of 1.222 W/cm2 in fuel cell (FC) mode and an electrolysis current density of 1.283 A/cm2 at an average voltage of 1.3 V in electrolysis cell (EC) mode, marking the highest reported values for FT-SOC stacks to date. These results surpass the performance of most large-sized planar SOC stacks. Post-operation analysis revealed excellent interfacial contact between components, contributing to the stack's high performance. This study underscores the potential of FT-SOCs in efficient power generation and electrolytic energy storage applications, providing insights that could facilitate their industrial application.

In this study, the Cu0.5Ni0.5MnCoO4 (CNMC) material was developed for use in the cathode of solid oxide fuel cells (SOFC). X-ray diffraction (XRD) confirmed the spinel structure and demonstrated compatibility with Yttria-stabilized zirconia (YSZ) electrolyte at elevated temperatures. The conductivity of CNMC was found to be between 28 and 55 S cm–1 at temperatures ranging from 700 to 900 °C. Oxygen-temperature programmed desorption (O2-TPD) revealed that CNMC powder possesses effective oxygen catalytic characteristics. To enhance performance, CNMC was combined with Gd0.1Ce0.9O2-δ (GDC, H2-bank Co. Ltd.) in a mass ratio of 3:7 (CG37). The thermal expansion coefficient (TEC) of this composite was measured at 12.8 × 10–6 K–1, closely matching that of YSZ and avoiding the issue of strontium segregation, eliminating the need for a barrier layer between the electrolyte and the cathode. The peak power densities of CG37 reached 1175 mW cm–2 and 905 mW cm–2 at 800 °C and 750 °C, respectively. CG37 underwent testing for 1000 h under constant-current discharge at 600 mA cm–2 and 750 °C, showing a voltage degradation rate of 2.5%/kh. The cell’s microstructure remained intact without any signs of elemental diffusion or segregation, indicating excellent chemical compatibility and stable structural integrity. This research is expected to further advance the study and utilization of novel solid oxide fuel cells.

The semiconductor-based tribovoltaic nanogenerator (TVNG) garners distinctive characteristics of direct current output at low internal impedance, rendering it great potentials for self-powered electronics. We present a polymeric TVNG for achieving enhanced electrical outputs and robustness through secondary doping strategy. By utilizing the dimethyl sulfoxide (DMSO) as a dopant, the transport properties of semiconducting poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) can be modulated. We then demonstrate that the tribovoltaic outputs can be significantly enhanced due to the improved conductivity of the PEDOT:PSS and the enlarged Schottky barrier at the dynamic metal-semiconductor interfaces. The quantity of the transferred charge per motion cycle can reach 150.48 mC m(-2) in contact-separation mode and 225.73 mC m(-2) in sliding mode. Meantime, the dopant improves the flexibility of the PEDOT:PSS and hence the mechanical robustness of TVNG, allowing stable outputs for similar to 100,000 contact-separation operations cycles or similar to 36,000 bending cycles. Furthermore, the device also demonstrates exceptional humidity resistance, but confirms a coupling of tribovoltaic effect and electrochemical effect in high-humidity conditions (relative humidity over 90%). Therefore, our findings provide insightful strategies for future optimization of practical tribovoltaic devices.

Propane dehydrogenation (PDH) is a vital petrochemical process. As an alternative to Pt and Cr-based catalysts, Ni-based catalysts used in PDH, however, exhibit low propylene selectivity with severe coking. This work aims to understand the role of different Ni species in PDH and achieve high propylene selectivity by inhibiting coking. Specifically, we obtained NiOx/Al2O3 catalysts with solely tetrahedrally coordinated Ni2+ (Ni-IV) by selectively removing microcrystalline NiOx using the impregnation-complexation strategy. The Ni sigma+ species derived from Ni-IV exhibited high propylene selectivity (similar to 88 %) and low coke yield (2.26 %) in PDH. In contrast, reducing microcrystalline NiOx to Ni-0 resulted in high methane selectivity and high coke yield (14.90 %). Theoretical calculations and experimental results indicate that this difference is attributed to the faster propylene desorption from Ni sigma+ as compared to that from Ni-0. Therefore, catalysts with well-confined Ni sigma+ are selective in PDH. This study offers a rational strategy for designing Ni-based PDH catalysts.

In this work, the performance of solid oxide fuel cells is improved by physically mixing Ce0(.9)Gd0(.1)O(1.95) (GDC) in La0(.6)Sr0(.4)CoO(3-)(& delta;) (LSC) cathode. The grain size and chemical compatibility of the powder were analyzed using X-ray diffraction. Scanning electron microscopy was used to observe the microstructure of powder and cells. The thermal expansion coefficients (TECs) of LSC-GDC powder with different mass ratios were tested (LSC:GDC = 10:0, 9:1, 8:2, 7:3, 6:4, and 5:5) and LSC-GDC (5:5) showed the minimal TEC (1.34 x 10(-5) K-1 at 650 & DEG;C). The cathodes with different mass ratios are prepared by screen printing. The symmetrical cell with LSC-GDC (5:5) had the smallest cathode polarization resistance (0.0801 & omega; cm(2) at 650 & DEG;C) and the lowest activation energy (1.12 eV). The button cell with LSC-GDC (5:5) exhibited the maximum power density (513 mW cm(-2) at 650 & DEG;C) and could be discharged for 550 h without significant degradation. The LSC-GDC (5:5) cathode was applied to a flat-tube solid oxide fuel cell and achieved a high power density of 552 mW cm(-2) at 0.8 V. The results show that the LSC-GDC (5:5) has a bright future in commercialization.

In this work, the Sm0.2Ce0.8O1.9 (SDC) buffer layer was used to replace the Gd0.1Ce0.9O1.95 (GDC) buffer layer to improve the long-term stability and performance of the solid oxide fuel cells (SOFCs) in the intermediate tem-perature (550-750 degrees C). The buffer layer was prepared by screen printing method. The micromorphology of the SDC buffer layer and the cell structures was observed by scanning electron microscopy (SEM). The electro-chemical impedance spectroscopy (EIS) results showed that the polarization resistance (RP) of the cell with SDC buffer layer was smaller than that of the cell with GDC buffer layer, reducing the RP values by 43.52% and 43.33%, respectively (SDC-cell: 0.12 omega cm2 at 650 degrees C and 0.27 omega cm2 at 600 degrees C). The maximum power density of the cell with SDC buffer layer is 560 mW cm-2 at 650 degrees C, which was 25% higher than that with GDC buffer layer. The long-term durability of the cell with SDC buffer layer was better than that of the cell with GDC buffer layer. These provide an excellent prospect for utilizing SDC buffer layer.

The oxidation of metal interconnects on the anode side in solid oxide fuel cells (SOFCs) leads to the degradation of the electrical properties, which affects the performance and long-term durability of SOFC stacks. In this study, we explored the oxidation behaviors of the SUS430 alloy interconnect in methanol-water anode atmosphere and investigated the possibility of using Sr2Fe1.5Mo0.5O6-delta (SFM) perovskite materials as an oxidation-resistant coating on the anode side of the SUS430 alloy interconnect. The bare SUS430 alloy and the SUS430 alloy with SFM coating (thickness: approximate to 40 mu m) were exposed in methanol/H2O anode atmosphere at 750 degrees C for 1000 h. After oxidation, a dense oxide scale with a thickness of 3.50 mu m was formed on the surface of the bare SUS430 alloy; the area-specific resistance (ASR) of the alloy increased from 1.70 m omega cm2 to 279.00 m omega cm2. By contrast, the thickness of the oxide scale on the surface of SUS430 alloy with protective SFM coating under the same working condition was 0.70 mu m; the ASR grows from 12.47 m omega cm2 to 14.51 m omega cm2. These results suggest that SFM forms an effective anode-side protective coating on the interconnects of SOFC stacks.