Energy Storage最新文献

Supercapacitors have gained substantial attention as devices for storing energy. This is because of their exceptional power density, rapid charging-discharging process, and longer lifetime. In this study, a hydrothermal synthesis procedure was followed to prepare two distinct nanostructures: cobalt ferrite (CoFe₂O₄) nanoparticles and cobalt ferrite-reduced graphene oxide (CoFe₂O₄/RGO) nanocomposite. Our results indicate that CoFe₂O₄ NPs has a specific capacity of 44.12 mA h g⁻¹ at 0.5 A g⁻¹, whereas CoFe₂O₄/RGO nanocomposite has a specific capacity of 198.62 mA h g⁻¹at the same current density. Subsequently, we utilized the positive electrodes as CoFe₂O₄/RGO nanocomposite and RGO as the negative electrode to fabricate asymmetric supercapacitor devices. For the CoFe₂O₄/RGO//RGO asymmetric supercapacitor device, we measure a specific capacity of 60.15 mA h g⁻¹ (@1 Ag⁻¹). The energy density and power density of the device are found to be 13.36 W h kg⁻¹ and 802 W kg⁻¹, respectively, at the same current density. Notably, when subjecting the CoFe₂O₄/RGO//RGO asymmetric supercapacitor devices to a 0.5 T external magnetic field, a significant enhancement in specific capacity was recorded, with an increase of ∼36% (81.96 mA h g⁻¹) at 1 A g⁻¹ of current density.

The global transition to sustainable energy systems demands high-performance thermal energy storage, with paraffin wax standing as a prominent phase change material (PCM) due to its high latent heat, chemical stability, and cost-effectiveness. However, its low thermal conductivity (about 0.2 W/m·K) and phase segregation significantly limit its practical application. While nanofillers and carbon additives can enhance conductivity, they often reduce latent heat, increase costs, and complicate processing. This study introduces a novel, sustainable solution by valorizing Algerian slack wax, a local petroleum refinery byproduct, as a multifunctional enhancer for paraffin. Composites with 6, 10, 15, and 20 mass% slack wax were formulated and characterized using the T-history method. The results demonstrate a breakthrough in simultaneous property enhancement, overcoming typical trade-offs. The 20% composite achieved a 35.65% increase in latent heat (from 106.93 to 145.06 kJ/kg), a 30.48% rise in specific heat (from 3.51 to 4.58 kJ/kg·K), and a 33% improvement in thermal conductivity (from 0.18 to 0.24 W/m·K in the solid state). Furthermore, the material's thermal responsiveness was enhanced, with a 25% reduction in solidification time (from 165 to 120 s) and a 20% faster melting rate (from 125 to 100 s). These improvements are attributed to molecular interactions that disrupt paraffin's crystalline order, facilitating more efficient phonon transport and energy distribution. By transforming an industrial waste into a high-performance PCM, this work provides a cost-effective, scalable, and circular pathway for advanced thermal storage, directly benefiting solar energy integration, building efficiency, and industrial waste heat recovery.

This study investigated metal-free organic dyes having D-π-A and D-A′-π-A frameworks for organic solar cells (OSCs). The influence of modifying the donor and internal acceptor in reference molecules (N, O, and S) on the structural, electronic, photovoltaic, and optical characteristics was analyzed by employing density functional theory (DFT). The UV–visible spectrum of the designed dyes was also simulated by employing time-dependent DFT (TD-DFT). The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and their energy gap (E_gap) are advantageous to understand the electron injection, electron transfer, and regeneration of the dye. The evaluated results suggest that short-circuit current density (J_SC), energy for dye regeneration (ΔG_reg), electron injection driving force (ΔG_inj), light harvesting efficiency (LHE), open circuit voltage (V_OC), density of state (DOS), and power conversion efficiency (η) are affected by the insertion of donors and internal acceptors. The dye N with Carbazole donor has an efficacy of 4.15% at J_SC of 15 mA cm⁻². The outcomes indicate that heteroatom-doped donors and inserting internal acceptors have an impact on absorption energies and improve the photovoltaic characteristics in the D-π-A arrangement, suggesting that these dyes are better sensitizers for the assembly of OSCs.

Effect of boron doping on the structure and hydrogenation-dehydrogenation characteristics of Ti₂CrV alloy has been investigated in detail. The alloys were prepared by arc melting method and were characterized using techniques such as XRD, SEM and EDX. With boron incorporation, the plateau pressure of hydrogen absorption increases with a decrease in enthalpy value, confirming destabilization of the hydride. The alloy, Ti_1.9CrVB_0.1, shows a maximum total hydrogen absorption capacity of 3.8 wt%, under ambient conditions with enthalpy and entropy of hydrogenation reactions, −48 kJmol⁻¹ and 112 Jmol⁻¹ K⁻¹, respectively. With further increase in B addition in the alloy, the hydrogen absorption capacity decreases to 3.5 wt% at room temperature. As prepared alloys exist in BCC structure which phase transforms into FCC structure up on hydrogenation. In situ hydrogen desorption temperature is found to decrease with an increase in B concentration. Around 30°C decrease in hydrogen desorption temperature was observed for Ti_1.9CrVB_0.1 alloy compared to parent Ti₂CrV alloy, confirming the improved dehydrogenation properties upon B addition. Compared to the parent alloy, Ti₂CrV, the hydrogen absorption rate of Ti_1.9CrVB_0.1 alloy improved significantly with an increase in the number of hydrogenation/dehydrogenation cycles due to the pulverization of the alloy. Studies confirmed that a small amount of B addition, (i.e., Ti_1.9CrVB_0.1 alloy) leads to better de-hydrogenation behavior, higher hydrogen absorption kinetics and improved cyclic stability compared to the parent Ti₂CrV alloy.

Metal-ion batteries (MIBs) are essential for transitioning to a cleaner and more sustainable energy future. By employing the density functional formalism, we have investigated the hexagonal (h) monolayer of BeS and BeTe as electrode materials for alkali (Li and Na) MIBs. The structural and thermodynamic stability, adsorption of Li/Na atoms, density of states, diffusion, and migration of atoms, as well as capacity, are investigated. The structures of h-BeS and h-BeTe remain stable upon adsorption of the adatoms, with improved electronic conductivity of these monolayers. The climbing image-nudged elastic band calculations estimate a low diffusion barrier of 0.16 eV (0.01 eV) for Li (Na) in h-BeS and 0.20 eV (0.16 eV) for Li (Na) in h-BeTe. Additionally, a maximum storage capacity of 580 mAh g⁻¹ for Li-ions and 1305 mAh g⁻¹ for Na-ions in h-BeS as well as 174 mAh g⁻¹ for both metal ions in h-BeTe, is estimated.

To address the issues of low noise and lack of portability in on-site partial discharge (PD) detection and testing of cables, the paper will present an AC excitation cable oscillation wave detection system using a capacitor bank power supply of energy. By adding two bidirectional high-speed solid-state switches at the output end of the inverter power supply in the traditional frequency modulation series resonant circuit, this paper uses capacitor banks to generate the required oscillation wave voltage, with the advantage of no switching noise interference. At the same time, to avoid pulse interference caused by the generator and reduce the sensitivity of PD detection, the following measures are taken in this article: using capacitor banks for power supply during the testing phase; the test interval utilizes mains power to charge the capacitor bank. This solves the problem of the system's dependence on the generator. After conducting high-capacity capacitance tests and 10 kV distribution cable application tests, the results showed that under the condition of capacitor bank power supply, the system can achieve equivalent 1 μ. The load of the F cable has increased to a peak of 24 kV, and the noise level of PD detection is below 10 mV. This indicates that the system in this article meets the requirements of offline PD detection tests for 10 kV power cables.

The pressing need for the global transition to sustainable energy requires efficient yet environmentally friendly advanced materials. Bioinspired energy materials, which replicate nature's optimized systems, have great potential to create a platform for solar energy harvesting breakthroughs, energy storage, and catalytic conversion. This review offers a synthesis of the latest developments in biomimetic photovoltaics, battery technologies, and catalytic systems, including their benefits, limitations, and prospects for commercialization. Moth-eye-inspired nanostructures in solar cells have realized 20%–40% enhancements in light absorption over planar surfaces. Bioinspired battery electrodes, with hierarchical porous architectures imitated from wood and coral structures, demonstrate up to 30% enhancement in ion transport and cycle life. Enzyme-mimetic catalysts, especially Ni–Fe hydrogenase analogues, provide hydrogen evolution efficiencies of more than 85%, on par with platinum-based systems but at below 10% of the cost. This review also covers frontier topics like biomimetic thermoelectrics and triboelectric nanogenerators, which have shown up to 30% increased energy conversion efficiency based on nature-mimicking nanostructuring. The uniqueness of this research is that it performs integrative analysis across various energy platforms based on comparative performance, lifecycle assessment, and technological readiness levels. It points to major research lacunas in scaling, stability, and material integration, and suggests routes to fill the laboratory discoveries–industry implementation gap. The originality of this review is in its cross-domain integration, comparative data synthesis, and sustainability-focused analysis of bioinspired energy materials. This review intends to be a go-to resource for understanding sustainable energy technology evolution through bioinspiration.

Solar air heaters (SAHs) are constrained in efficiency and operational duration by the intermittency of solar energy. This study addresses these constraints by investigating the use of phase change materials (PCMs) for thermal storage. However, PCMs are hindered by their low thermal conductivity and integration challenges. In this research, a novel double-fin counterflow SAH was developed using polygonal galvanized iron absorber panels and transverse rectangular fins. The fins were integrated with a phase-change material composed of paraffin wax and iron filings (2 L of paraffin and 50 g of iron filings). Experiments were conducted in Hawija city, Iraq (35.4586°N, 43.8319°E), over 6 consecutive clear days, evaluating setups with and without PCMs under actual environmental conditions. Key parameters, including efficiency, output temperature, and heat gain, were assessed. The results showed that the inclusion of PCM increased the daily thermal efficiency by 15.2% (from 31.04% to 35.75%), extended heat delivery by 5 h after sunset (until 8:00 p.m. compared to 5:00 p.m. without PCM), and reduced the peak outlet temperature by 7.3% (32.9°C vs. 35.5°C at noon). Furthermore, the average daytime temperature was elevated by 28.8% (18.3°C vs. 14.2°C). This study presents an economical solution for solar thermal stabilization, specifically designed for agricultural drying and building heating in sunny regions. The proposed design addresses PCM conductivity limitations and extends SAH operation beyond daylight hours.

This study deals with optimizing solar collector performance, using porous media of glass spheres and metal fibers to compare the effect of each on thermal performance. The research problem stems from the need to improve heat absorption and increase the efficiency of solar energy conversion, given the environmental challenges and high costs of conventional energy. The study was carried out practically through the manufacture and installation of a pneumatic solar collector on the roof of the building of the Renewable Energies Research Unit at the Hawija Technical Institute, where the performance of the two systems was measured using precision instruments. The results showed that the metal fibers absorbed more heat during peak periods; the power gain reached 200 W compared to 190 W when using glass balls, but they lost heat quickly after that. In contrast, glass spheres retained heat for longer periods, resulting in a higher thermal efficiency of 57% compared to 52% for metal fibers. These results indicate that the performance of the solar collector was better when using glass balls due to their ability to store heat for longer periods and reduce energy loss, making them a more efficient and sustainable option in solar heating and ventilation systems. The novelty of this study lies in its direct experimental comparison between two distinct types of porous media—glass balls and metal fibers—under identical conditions, which has not been previously explored in the literature. This comparison offers fresh viewpoints about their relative effectiveness in thermal storage and heat transfer within solar air collectors.