Materials for Renewable and Sustainable Energy最新文献

The cathode in a molten carbonate fuel cell (MCFC) was made using the tape casting method from a slurry with a suitable chemical composition consisting of porogen, allowing it to achieve a porous structure. Currently used porogens in creating cathode structures are synthetic polymers, which release hazardous substances into the environment during thermal removal. Therefore, it is very important to find a safer alternative before industrial production of fuel cells begins and reduce its impact on the environment. The research aimed to analyze the possibility of using various porogens to obtain a fuel cell's cathode microstructure and compare them to a reference cathode. The electrodes were produced using cheap, accessible, and natural porogens. Chosen porogens were post-production waste materials such as wheat straw, hemp, and beet pulp. They were used solo or coupled to create the cathode of MCFC, thoroughly characterized in the context of morphology, structure, and chemical composition. After optimization, final MCFC cathodes were characterized by SEM, Archimedes porosimetry, gas porosimetry, and gas permeability. The highest power density (100 mW/cm²) was obtained for the cathode, which was made with starch and straw, while starch and PVB enabled the achievement of 90 mW/cm² of the MCFC cathode.

Alternative proton exchange membranes (PEMs) with high proton conductivity must be fabricated at reasonable costs to qualify as commercially used proton-exchange membrane fuel cells (PEMFCs). As a result, composite membranes containing sulfonated poly(ether ether ketone) (SPEEK) blended with various quantities of partially oxidized polyvinyl alcohol (OPVA) at 5 wt%, 10 wt%, and 20 wt% were developed for PEMs. At room temperature, the water uptake capacities of the SPEEK membranes containing 5, 10, and 20 wt% OPVA were 45%, 75%, and 109%, respectively. Correspondingly, the proton conductivities of SPEEK containing 5, 10, and 20 wt% OPVA were 22, 48, and 80 mS cm⁻¹ at 110 °C, respectively. Compared with prestine SPEEK, OPVA/SPEEK have greater strength, stiffness, and thermal stability. The characterization results indicated that the strong hydrogen bond network that evolved between OPVA and SPEEK provided more jump sites for proton transfer. This study confirmed that OPVA/SPEEK membranes are effective as proton exchange membranes.

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A two-step electrodeposition approach was applied to deposit Sn/C layers on a Ni foam substrate. The first step was the deposition of the Sn layer using two electrodeposition modes (direct and pulsed electrodeposition) with different parameters (duty cycle, time on/off, and effective time). The second step was to deposit carbon on the Sn layer by direct electrodeposition. The surface morphology, chemical composition, and phases of deposited layers were investigated and the electrochemical behavior of Sn/Ni and C/Sn/Ni anodes was characterized. The pulsed electrodeposition technique with a lower duty cycle (15% duty cycle with time ratio t_on/_off = 3/17 for 2 min) produced more uniform and compacted deposits, compared to the non-uniform and dendritic morphology obtained after high duty cycles (50%) as well as direct electrodeposition. After the direct electrodeposition of carbon on the pulsed electrodeposited Sn, a uniform layer containing ~ 10% C, 38% Sn, 45% Ni, and 7% O, was detected. Analysis of this layer confirmed the presence of Ni, Sn, and amorphous C. Electrochemical characterization showed that the C/Sn/Ni anodes with a 94 Ω polarization resistance, a 0.105 V/decade anodic Tafel slope and 0.202 V/decade cathodic Tafel slope manifested the highest apparent and intrinsic catalytic activities. The peak current for the C/Sn/Ni samples was higher than the peak current for the Sn/Ni samples at all scan rates, indicating higher electrochemical reactivity. The linear relationship between the peak current and the scan rate's square root suggests that diffusion controls the charge transfer process.

Solar energy harvesting and conversion has attracted a lot of scientific interest because solar energy is believed to be clean and sustainable. In this study, we report the synthesis of porous TiO₂ by sol-gel method and later doped with Thulium rare earth ions (Tm³⁺) for potential application in organic solar cells as electron transport layers (ETL). Additionally, density functional theory (DFT) calculation was performed with CASTEP computational suite to explore further the optoelectronic and charge transfer mechanisms in the Tm(III)-doped TiO₂ nanomaterials. Thereafter, the experimental material’s band gap values were extracted and used in the numerical simulation of the designed organic solar cell with a general configuration of FTO/TiO₂/PBDB-T/ITIC/Cu₂O/Ag, via SCAPS-1D numerical simulator. The experimental results showed a steady reduction in the band gap of TiO₂ with increased Tm³⁺ doping. The electrical conductivity properties showed an enhanced feature when TiO₂ was doped with Tm³⁺ nanoparticles. The calculated band gap from the density functional theory study shows a similar decreasing band gap trend with that of the experimental data, suggesting the transport properties from DFT are sufficient to describe the experimental data. The electronic transfer behaviour is analogous to metal-metal and metal-oxides transport features, which can be attributed to Ti – Tm and Tm – O – Ti hybridizations, as indicated in the orbital state alignment. The best performing modelled device with Tm(III)-doped TiO₂ (1.0 mol%) as ETL attained a PCE of 21.83%, V_oc of 1.54 V, J_sc of 31.87 mA cm^− 2 and FF of 44.44% which was attributed to better charge transfer characteristics and effective band alignment between the ETL and absorber, thus, better efficiency. The study proposes that Tm(III)-doped TiO₂ can act as a suitable n-type material that can propel the realisation of high-performance OSCs for commercialization in the future.

This work improved energy efficiency, stability and energy stability in organic and organic perovskite solar cells, by using titanium dioxide as anti-reflective coating on silver. The use of graphene oxide-nickel oxide layer as a hole-transporting layer enhanced carrier mobility in addition to incrementing stability. The outcomes that have been meticulously extracted and analyzed from the finite-difference time-domain (FDTD) simulations provide compelling evidence that this particular methodology can be adeptly utilized to significantly enhance the capability to attain a remarkably broad absorption spectrum across a wide range of wavelengths, specifically those identified frorm 200 nm to 900 nm, which are of critical importance in solar cell applications. Optical analysis was conducted by Maxwell method. Dielectric plasmonic wire grating was proposed to increase optical absorbance and achieve maximum current. The electrical analysis of the structure was based on Poisson’s equations. Optical analysis of the inorganic halide perovskite revealed current density, open circuit voltage, fill factor, and power of 34.294 mA/cm², 1.04 V, 0.83369817, and 1.64 mA/cm². The energy conversion efficiency was also 29.3%.

Non-fullerene acceptors are promising materials for organic solar cells because of their flexibility and low cost; however, their long-term stability remains a critical challenge. In this study, we investigate the degradation mechanisms of conventionally structured solar cells (ITO/PEDOT: PSS/PM6/Y7/PDINO/Ag) under different environmental conditions: nitrogen preservation, encapsulation, and air exposure. Using the metal-insulator-metal (MIM) model, we simulate the current-voltage characteristics and extract key parameters to understand the physical mechanisms governing device degradation. The results show that air exposure primarily affects the anode interface, reducing the interfacial dipole energy and shifting the Fermi-level alignment of PEDOT: PSS, which is crucial for efficient hole extraction. This process leads to a deterioration in the hole transport properties over time, significantly affecting device performance. In contrast, the cathodic interface remains stable, suggesting that degradation is largely driven by changes in the hole transport layer. These findings provide critical insights into the interfacial degradation mechanisms of the NFA-based solar cells. Understanding these effects will aid in the development of strategies to enhance the stability and efficiency of organic photovoltaic devices for long-term operation.

Granular materials like sand have gained importance in thermal storage applications due to their stability and cost-effectiveness. However, excessive usage of sand can pose environmental issues. This study investigates recycled construction materials such as glass, asphalt, ceramic, and concrete as alternatives to natural sand for low-temperature TES applications. The materials were processed to similar grain sizes and evaluated for their chemical, thermophysical, and thermal storage properties through a six-hour charging cycle at 60 °C. XRF analysis revealed significant compositions, including high oxygen and silicon content in concrete and sand, respectively. Results indicate that sand with 0.189 W/m K recorded the highest thermal conductivity compared with concrete 0.172 W/m K, glass 0.131 W/m K, ceramic 0.159 W/m K and asphalt 0.159 W/m K. A higher specific heat capacity was observed in concrete at 755 J/kg K, followed by asphalt at 732 J/kg K, glass at 708 J/kg K, and sand at 688 J/kg K. However, ceramic is categorized for a lower specific heat capacity of 682 J/kg K. Absolute density evaluation indicates that sand is the densest material with 2662 kg/m³, contrary to concrete 2480 kg/m³, glass 2421 kg/m³, ceramic 2285 kg/m³, and asphalt 2436 kg/m³. More to the point, the Ragone plot for specific power and energy highlighted that ceramic has a rapid energy release and concrete demonstrated sustained energy storage capabilities. Volumetric power and energy density assessments indicated sand's outstanding performance. However, concrete registered a superior thermal storage among recycled materials. The results highlight that recycled materials, specifically concrete can be used for thermal storage applications like water heating in poor communities.

In this work, different varieties of dye sensitized solar cells are fabricated by simple fabrication process. In this fabrication extract of butea monosperma flower, methylene blue and methyl orange dyes are used as sensitizers. The photovoltaic performance of dye sensitized solar cells (DSSCs) has been studied. The performances of two different types of photo-electrodes are also tested in this work. The morphology and bandgap of TiO₂ (titanium dioxide) and ZnO (Zinc oxide) was observed from XRD, FTIR spectroscopy and UV-vis Spectrum. It is found that TiO₂ based DSSCs have better performance. It also observed that the current density and efficiency was increased from 7.46 to 12.9 mA/cm² and from 1.34 to 6.8% respectively when using methyl orange as a dye. Hence it can be said that methyl orange dye enhanced the photovoltaic performance of DSSC.

Herein, human hair-derived activated carbon (HH-AC) with remarkable physisorption properties such as high surface area and well-balanced micro- and mesopores, is synthesized by chemical activation method using potassium hydroxide (KOH). The activated carbon is synthesized at different ratio of charred human hair and activator as 1:1, 1:2 and 1:3 for HH AC(11), HH-AC(12) and HH-AC(13), respectively. These activated materials are characterized by a powder X-ray diffraction (XRD), Laser Raman spectroscopy, Scanning electron microscope (SEM), and (:{text{N}}_{2}) adsorption/desorption isotherms. To examine the influence of the micro-mesopore ratio with high surface area on supercapacitor behavior, all samples are tested in a three-electrode using 2.5 moles of potassium nitrate (2.5 M KNO₃) as electrolyte solution. The results show that HH-AC(12) sample which has micro to mesopore-balanced(:(50:50):) exhibited superior electrochemical performance with specific capacitance of (:215:text{F}:{text{g}}^{-1}) and (:125.8:text{F}:{text{g}}^{-1}) in the negative and positive potential, respectively at (:1:text{A}::{text{g}}^{-1}). The sample HH-AC(11), which is dominated by micropores, showed lower rate capability and specific capacitance despite the huge surface area.Whereas the HH-AC(13) sample with mostly mesopores achieved higher rate capability compared to the others. The HH-AC(12) is further examined in a 2-electrode setup to form a symmetric device. The results show a specific energy of (:16:text{W}text{h}:text{k}{text{g}}^{-1}) and a specific power of (:375:text{W}:text{k}{text{g}}^{-1}) at (:0.5:text{A}:{text{g}}^{-1}). The device demonstrates outstanding capacitance retention of (:97text{%}) after 10,000 cycles. Thus, ACs with micro to mesopores-balanced are potential candidates for supercapacitor applications.