Search Results (626)

A facile and scalable strategy is presented in this work for the direct fabrication of binder-free copper (Cu) oxide nanospheres on the Cu foam surface via femtosecond (fs) laser ablation for energy storage applications, primarily in supercapacitors. XRD and EDX analyses confirmed the presence of Cu oxides. At the same time, SEM images indicated that the resulting Cu oxide nanospheres range from ~70 to 700 nm in size, with hierarchical surface features such as laser-induced periodic surface structures (LIPSS), which provide additional active sites for reversible redox reactions. The prepared fs laser-ablated Cu foam samples, with Cu oxide nanospheres (Femto-Cu), can store 8 to 10 times more energy than the bare Cu foam, with ~87.7% capacitance retention after 10,000 charging–discharging cycles. Further, in-depth kinetic investigations revealed that the charge is stored through both surface-controlled capacitive behavior and a diffusion-controlled mechanism. These findings highlight the effectiveness of fs laser-induced structuring in improving the charge-storage characteristics of Cu foam and provide a promising route for developing high-performance, binder-free electrodes in a single step. Full article

Nonaqueous potassium-ion batteries (KIBs) are emerging as promising next-generation energy storage systems owing to their abundant resources and high energy density. However, their large-scale application is hindered by structural degradation and sluggish kinetics resulting from the large ionic radius of K ions. Engineering electrode materials with open frameworks, such as two-dimensional (2D) layered structures, present an effective strategy to address these challenges by providing rapid ion diffusion pathways and robust host structures. Herein, a rational interlayer engineering strategy is developed by intercalating phenylamine derivatives with varying molecular sizes (P-butylaniline: PTA, P-Methylaniline: PMA, and phenylamine: PA) into layered 2D VOPO₄ nanosheets. The intercalation of PANI derivatives progressively expands the interlayer spacing from 0.76 nm (pristine VOPO₄) to 1.58, 1.85, and 2.09 nm, while maintaining the structural integrity of the layered framework. Notably, the regulated interlayer expansion (from 0.76 to 2.09 nm) not only provides enlarged diffusion pathways for rapid K⁺ ion intercalation/deintercalation kinetics, but also facilitates the formation of oxygen vacancies that may serve as additional active sites for potassium storage. By correlating the electrochemical performance with the modulated interlayer distances, it is established that a preferred spacing of 1.85 nm achieves the best synergy between fast kinetics, high capacity, and structural stability. As expected, the electrode with the optimal interlayer spacing (1.85 nm) exhibits superior potassium-ion storage performance, delivering a high reversible capacity of 333.2 mAh g⁻¹ at 0.1 A g⁻¹ over 100 cycles and exceptional rate capability with 205.7 mAh g⁻¹ retained at 1 A g⁻¹, as well as maintaining remarkable stability up to 600 cycles even at high rates. This work innovatively proposes phenylamine derivative-enabled interlayer regulation as a promising approach for designing high-performance VOPO₄-based electrode materials. Full article

The objective of this study was to predict the degradation kinetics of vitamin C in camu camu and naranjilla juices using accelerated storage tests. The juices were produced under controlled processing conditions, including physicochemical standardization, pasteurization, and hot filling into glass containers. They were then stored at 35, 45, and 55 °C for 21, 14, and 7 days, respectively. The vitamin C content was quantified using high-performance liquid chromatography, showing a progressive decrease depending on temperature. The kinetic data were fitted to zero-order and first-order models, as well as to the nonlinear Weibull model, the latter presenting the best statistical fit (R² = 0.9678–0.9931) and adequately describing the nonlinear degradation behavior of vitamin C. Temperature dependence was modeled using the Arrhenius equation, allowing activation energy to be estimated and confirming temperature-dependent degradation behavior in both juices, with different thermal responses depending on the modeling approach. Likewise, shelf life (t₈₀) was estimated using the Weibull model and showed a significant reduction with increasing storage temperature. Arrhenius-based shelf-life predictions suggested greater vitamin C retention in camu camu juice at lower storage temperatures, whereas naranjilla exhibited a more pronounced decrease as temperature increased. The physicochemical parameters (pH, acidity, and °Brix) showed moderate changes, maintaining the stability of the system during storage. The results confirm the applicability of the Weibull model to describe vitamin C degradation in complex matrices and highlight the importance of thermal control in the preservation of bioactive compounds in tropical juices. Full article

Addressing the challenges of fluctuating renewable energy integration and stable green ammonia production, this study develops and optimizes a deeply integrated system comprising Solid Oxide Electrolysis Cells (SOEC), Liquid Air Energy Storage (LAES), Air Separation Units (ASU), and Haber–Bosch (HB) synthesis. We constructed a simulation model in Aspen Plus incorporating Ru/C catalyst kinetic parameters to analyze key subsystem parameters and optimize operating conditions based on maximized economy and efficiency. At the integrated system level, a parametric analysis of ammonia condensation temperature was further conducted to investigate the coupling characteristics. Using real power output data from Inner Mongolia, we formulated a dynamic energy scheduling strategy satisfying 24-h self-balancing constraints. Results indicate that a system producing 1415 tons of ammonia per day achieves a maximum hourly integrated profit of 69,838 CNY under optimal conditions: a hydrogen-to-nitrogen ratio of 2.98:1, operating pressure of 169 bar, reactor inlet temperature of 380 °C, and ammonia condensation temperature of −9 °C. Increasing the LAES throttle valve outlet pressure from 1 bar to 9 bar improved round-trip efficiency from 52.65% to 72.18%. The integrated-level parametric analysis reveals that the specific electricity consumption per unit mass of ammonia exhibits a non-monotonic trend with a minimum of 8.67 kWh/kg at −10 °C, reflecting the trade-off between refrigeration power consumption and cold energy recovery. In dynamic scheduling scenarios, the system maintains a maximum constant load of 45.78 MW with a steady-state liquid ammonia output of 6543 kg/h. This work optimizes both economic performance and system stability, providing a significant reference for the large-scale development of green ammonia systems. Full article

The rational design of electrode architectures is essential for advancing high-performance supercapacitors. In this study, Nd₂O₃ electrodes with controlled structural features were developed via a polyacrylic acid (PAA)-assisted hydrothermal approach. By systematically tuning PAA concentration, the growth mechanism of Nd₂O₃ was effectively regulated, leading to a distinct morphological transition from compact agglomerates to well-defined hierarchical structures. The optimized Nd₂O₃-P2 electrode exhibits a porous and interconnected architecture, providing enhanced electrolyte accessibility and shortened ion diffusion pathways. This structural optimization significantly improves electrochemical performance, delivering a high areal capacitance of 26.889 F/cm² at 10 mA/cm², along with excellent rate capability and reduced internal resistance. Kinetic analysis reveals that charge storage is predominantly governed by diffusion-controlled Faradaic processes, with the optimized structure facilitating rapid ion transport and efficient redox activity. Additionally, the electrode demonstrates excellent cycling durability, retaining 87.08% capacitance over 12,000 cycles. An asymmetric supercapacitor assembled using Nd₂O₃-P2 and activated carbon achieves stable operation up to 1.5 V, delivering good capacitance retention (81.2%) after 7000 cycles. This work highlights the effectiveness of PAA-induced structural tuning and provides a practical strategy for developing advanced rare earth oxide-based electrodes for energy storage applications. Full article

Carbon-based supercapacitors are fundamentally limited by the tortuosity of conventional microporous architectures, which restricts ion transport kinetics and impedes the full utilization of active sites, particularly under high-rate conditions. Herein, we report a molten-salt-assisted topological transformation strategy to fabricate nitrogen-doped hierarchical porous carbon (A-ZC) featuring a distinctive open-windowed hollow architecture. This design effectively mitigates the tortuosity of conventional microporous networks, creating low-resistance pathways that facilitate rapid ion flux and deep electrolyte penetration. Consequently, the symmetric supercapacitor delivers a high energy density of 11 Wh kg⁻¹ at a power density of 250 W kg⁻¹. Moreover, it exhibits outstanding cycling stability, retaining 98.9% of its initial capacitance after 20,000 cycles. By elucidating the correlation between salt-induced microstructural evolution and electrochemical kinetics, this work offers a robust blueprint for overcoming the intrinsic limitations of traditional porous architectures in high-performance energy storage. Full article

Monoethanolamine (MEA) remains the predominant solvent for carbon dioxide (CO₂) capture due to its rapid reaction kinetics, substantial absorption capacity, and demonstrated industrial effectiveness. Despite its established status, MEA-based systems are undergoing continuous development to lower energy requirements, enhance solvent stability, and expand operational adaptability. This review provides a critical assessment of recent progress in MEA-based CO₂ capture, encompassing molecular-level understanding, advancements in reactor and process design, solvent modification strategies, and system-wide optimization. Recent theoretical and experimental research has improved the understanding of CO₂ absorption mechanisms in MEA, highlighting the effects of reaction-product buildup, interfacial phenomena, and free amine availability on mass-transfer efficiency. Reboiler duty and comparable work have significantly decreased as a result of advances in process intensification, improved regeneration systems, and energy-integration techniques. New hybrid strategies that partially decouple capture from thermal regeneration, such as combined absorption–mineralization pathways, show promise for long-term CO₂ sequestration. To address regeneration energy, corrosion, degradation, and cyclic stability, this review examines advances in MEA-based solvents, including aqueous blends, non-aqueous and biphasic systems, ionic liquids, and deep eutectic solvent hybrids. It also critically assesses the trade-offs of developments in intensified contactors, surfactants, nanomaterials, and catalysts. The growing role of digital optimization, machine learning, and computational modeling in MEA process design and control is highlighted. Overall, this analysis underscores MEA’s continued importance as a versatile platform for next-generation carbon capture, utilization, and storage. Full article

Rechargeable magnesium batteries are promising candidates for next-generation energy storage systems due to their intrinsic safety, natural abundance, and high volumetric capacity. However, their practical application remains limited by sluggish Mg²⁺ transport, electrolyte instability, and low cathode utilization. In this work, a halogen-free electrolyte (HFE) based on Mg(NO₃)₂ in an acetonitrile/tetraethylene glycol dimethyl ether (ACN/G4) solvent system is modified using the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) to form HFE_IL, with the aim of enhancing ionic transport and interfacial stability. In parallel, a sustainable sulfur cathode integrated with microalgae-derived hard carbon (S_C) is developed to improve electronic conductivity and suppress polysulfide shuttling. Structural and spectroscopic analyses confirm that the incorporation of the ionic liquid preserves the electrolyte framework while tuning the solvation environment. Electrochemical characterization (EIS, CV, LSV, GCD, and Mg stripping/plating measurements) reveals that HFE_IL exhibits reduced bulk and interfacial resistances, a significantly lower activation energy (0.0173 eV compared to 0.14 eV), and an increased Mg²⁺ transference number (~0.8). Furthermore, enhanced Mg²⁺ diffusion (~10⁻¹³ cm² s⁻¹) and improved charge-transfer kinetics are achieved compared to the pristine electrolyte. Symmetric Mg‖Mg cells demonstrate stable stripping/plating behavior with reduced polarization over 100 h. In full Mg‖electrolyte‖S_C cells, the HFE_IL system delivers a higher discharge capacity (~575 mAh g⁻¹) compared to the pristine electrolyte (~437 mAh g⁻¹), indicating improved reversibility and Mg²⁺ utilization. This study demonstrates that ionic-liquid modification of halogen-free electrolytes, combined with sustainable carbon–sulfur cathodes, provides an effective strategy to enhance Mg²⁺ transport, interfacial stability, and overall electrochemical performance in magnesium batteries. Full article

Hydrogen storage remains a key challenge in the transition toward sustainable energy systems, particularly for applications requiring high energy density and safe operation. Among various solid-state storage materials, magnesium hydride (MgH₂) is considered highly promising due to its high hydrogen capacity, low cost, and good reversibility; however, its practical application is hindered by slow kinetics and high thermodynamic stability. In this study, Mg and Ni coatings were deposited on Al₂O₃ based substrates using a direct current plasma spraying technique to develop a composite system for enhanced hydrogen storage performance. The influence of plasma torch parameters on coating characteristics was investigated, and the hydrogenation behavior was analyzed under controlled conditions (350 °C & 200 °C, 5 atm H₂). The structural, morphological, and compositional evolution of the coatings before and after hydrogenation was examined using SEM, EDS, XRD, and FTIR techniques. Results demonstrate that plasma-sprayed Mg coatings undergo significant morphological transformation after hydrogenation, including surface cracking, increased porosity, and phase conversion to MgH₂, confirming effective hydrogen uptake. In contrast, Ni coatings exhibit limited hydride formation but play a catalytic role by facilitating hydrogen dissociation and improving surface reactions. The influence of plasma power on coating quality and hydrogenation efficiency was also identified, with higher power leading to improved coating uniformity and enhanced MgH₂ formation. Additionally, a reaction–diffusion model was developed to evaluate the effect of temperature and hydrogen pressure on hydride layer growth. The model predicts an optimal temperature range (~300–330 °C) for MgH₂ formation, beyond which thermodynamic instability limits hydride stability. Overall, the study demonstrates that plasma-sprayed Mg/Ni coatings on granular substrates represent a promising approach for developing efficient hydrogen storage systems, combining improved kinetics, structural stability, and scalable processing. Full article

Spent coffee grounds (SCGs) are abundant byproducts generated during coffee processing that are unsuitable for storage and subsequent value-added utilization owing to their high moisture content and water activity (a_w). This study investigated the effects of different infrared power levels (800, 900, and 1000 W) on drying kinetics, product quality, and energy efficiency to determine the preferred drying parameters for SCGs. The initial moisture content and a_w of SCGs were 63.56% (wet basis) and 0.95, respectively. To enhance mechanistic understanding, the drying data were fitted to four mathematical models, with the Midilli and Page models providing the best fit (R² > 0.99). Drying experiments were conducted under a sample thickness of 0.7 cm and a loading of 500 g, with a final moisture content of <10% as the drying endpoint. The results showed that as infrared power increased, drying time decreased from 30 to 24 min and the drying rate significantly increased from 10.32 to 12.77 g H₂O/min (p < 0.05). The drying process was mainly characterized by a falling-rate period, with the effective moisture diffusivity ranging from 0.97 to 1.15 × 10⁻⁸ m²/s and increasing with rising power, indicating that internal moisture diffusion was the dominant drying mechanism. The final a_w of each treatment group was ≤0.60, indicating good storage stability. Color analysis showed that the color differences in treatments at higher power levels (900 W and 1000 W) were significantly lower than those at lower ones (p < 0.05). While the specific energy consumption (SEC) showed a marginal decrease from 5.80 to 5.68 kWh/kg at higher power, a comprehensive evaluation of drying efficiency, quality characteristics, and energy consumption indicated that 1000 W was the preferred infrared drying power under the conditions employed in this study. These results confirm that infrared drying is an efficient stabilization method with strong potential for rapid stabilization of food processing byproducts. Full article

Formic acid (FA) has emerged as a promising liquid hydrogen storage material, yet efficient photothermal dehydrogenation catalysts with high activity and H₂ selectivity remain challenging. Herein, a polymetallic synergistic PdCu/M-ZNC (where M represents the co-doped In, Sn and Mo species) is fabricated by molten-salt-assisted pyrolysis of ZIF-8 precursors followed by metal incorporation. The unique molten salt environment effectively preserves the porous architecture of ZIF-8, enabling the secure anchoring of PdCu alloy nanoparticles onto the carbonaceous matrix enriched with M-N_x coordination sites. Under light irradiation, the PdCu alloy sites kinetically accelerated the overall adsorption and activation of FA molecules. Based on empirical observations and corroborated by the established literature, this alloying effect was inferred to facilitate the C-H bond cleavage and HCOO* desorption processes. Concurrently, the M-N_x sites act as efficient electron transfer channels, facilitating the rapid coupling of photogenerated electrons with protons (H⁺) to evolve H₂. Consequently, the optimal catalyst exhibits an enhancement in gaseous product yield (404.46 mmol/g/h) and H₂ selectivity (67.49%) at 75 °C. This work offers a catalyst design that aligns with several principles of green chemistry: it maximizes the atom utilization of precious Pd, incorporates synergistic non-precious metals within MOF-derived frameworks to enhance stability, and leverages solar energy to drive hydrogen production under mild conditions, presenting a more sustainable pathway for hydrogen release from liquid carriers. Full article

Nickel-rich NMC-811 is a benchmark cathode material for high-energy density lithium-ion batteries due to its high specific capacity (>200 mAh g⁻¹) and operating voltage (~3.8 V). However, its strong surface reactivity toward atmospheric species, particularly moisture and CO₂, poses significant challenges during storage and processing, leading to the formation of LiOH- and Li₂CO₃-rich surface layers. Although the effects of humid air have been widely investigated, a direct comparison between high relative humidity and pure CO₂ exposure remains limited. Here, we systematically examine the morphological, structural, chemical, and electrochemical evolution of commercial NMC-811 electrodes after 5 h exposure to 80% relative humidity or CO₂-saturated atmosphere. Moisture treatment induces substantial surface reconstruction, lattice shrinkage, and increased cation disorder, accompanied by extensive hydroxide and carbonate formation. In contrast, CO₂ exposure mainly modifies the outermost surface layer without significant bulk structural changes. Electrochemical testing reveals that CO₂-treated electrodes display higher initial polarization but quickly recover near-pristine performance, whereas humidity-treated electrodes exhibit persistent kinetic limitations, accelerated capacity fading, and earlier end-of-life. Overall, degradation severity follows the trend: pristine < CO₂ < RH 80%, highlighting the dominant role of moisture in irreversible structural deterioration. Full article

Direct ocean carbon capture (DOC) has emerged as a promising strategy for mitigating atmospheric CO₂ levels and addressing ocean acidification. Unlike direct air carbon capture methods, DOC leverages the ocean’s vast carbon storage capacity, offering a scalable and efficient route for carbon dioxide removal. This systematic comparative review categorizes existing DOC methods into three types: (1) biological carbon capture, which relies on photosynthesis by microalgae and marine microorganisms; (2) electrochemical carbon capture, which utilizes water electrolysis to generate H⁺ and OH⁻ ions for pH-driven CO₂ removal; and (3) physical carbon capture, which employs hollow fiber membranes to directly separate CO₂ from seawater. For each technology, we evaluate efficiency, energy consumption, cost, technology readiness level (TRL), scalability, and major challenges. By integrating recent pilot data and providing a critical assessment, this review offers a roadmap for future research in direct seawater CO₂ capture. The comparative analysis reveals that electrochemical methods achieve the highest efficiency (60–85%) but face membrane fouling and electrode degradation challenges, while biological methods offer low-energy operation but suffer from slow kinetics and high harvesting costs, and membrane-based methods provide high removal rates (up to 94%) but require improved fouling resistance. Full article

Manganese-based cathodes offer high capacity, low cost, and safety for aqueous zinc-ion batteries (AZIBs), yet suffer from Mn dissolution, Jahn–Teller distortion, and sluggish Zn²⁺ kinetics. Herein, a Zn/Co co-doped MnO nanoporous carbon composite (denoted as ZnCo-MnO@NPC) derived from a bimetallic ZnCoMn metal–organic framework (ZnCoMn-MOF-74) is successfully synthesized and proposed as a high-performance cathode to address these challenges. The introduction of Zn²⁺ increases the initial specific capacity of MnO, while Co doping effectively suppresses the Jahn–Teller distortion and improves the integrity of the structure. Furthermore, the nanoporous carbon matrix facilitates electrolyte infiltration and accelerates ionic transport. To further suppress dendrite growth and enhance cycling stability, a zeolitic imidazolate framework (ZIF-8) protective layer is engineered on the zinc anode (denoted as ZIF-8@Zn), effectively mitigating dendrite formation. The ZnCo-MnO@NPC//ZIF-8@Zn full cell demonstrates superior electrochemical performance, delivering 281.3 mAh g⁻¹ at 0.1 A g⁻¹ and retaining 98.7% of this value after 3500 long-term cycles at 2.0 A g⁻¹, a remarkable finding that underscores its potential for high-performance energy storage. Collectively, this work highlights that transition metal ion doping represents an effective way to design efficient high-performance MOF-derived cathodes of AZIBs. Full article

Sodium-ion batteries (SIBs) represent a compelling alternative to lithium-ion batteries for grid-scale energy storage, owing to the high natural abundance and low cost of sodium resources, as well as their strategic alignment with national energy security priorities. Nevertheless, the sluggish Na⁺ diffusion kinetics and limited specific capacity of anode materials continue to impede practical deployment. Herein, nitrogen-doped carbon-coated TiO₂ nanofibers (TiO₂/C-N) were rationally engineered through a facile electrospinning route integrated with synergistic defect and coating engineering. The in situ-formed N-doped carbon shell establishes a continuous, high-conductivity electron-transport network while simultaneously buffering volumetric strain during repeated (de)sodiation, thereby preserving long-term structural integrity. Electrochemical assessments demonstrate that the TiO₂/C-N electrode delivers a reversible specific capacity of 233.64 mAh g⁻¹ at 0.1 A g⁻¹ (initial Coulombic efficiency 54.13%). Quantitative kinetic analysis reveals a pronounced pseudocapacitive contribution of 41.4% at 1.2 mV s⁻¹, confirming a surface-controlled Na⁺ storage pathway that markedly enhances rate capability. Moreover, the electrode retains 245.5 mAh g⁻¹ after 150 cycles at 1 A g⁻¹, underscoring exceptional cycling stability. This work elucidates the synergistic regulation of N-doped carbon coating and pseudocapacitive kinetics in TiO₂-based anodes, offering a robust design strategy for high-rate, long-cycle-life SIB anodes. Full article