The development of high‐energy‐density (HED) hydrocarbon fuels derived from renewable feedstocks is of significant interest for advanced rocket and missile propulsion systems requiring compact fuel storage and high volumetric energy output. In this study, cyclopropanated β‐pinane (CPBP) was synthesized from bio‐derived β‐pinene through Simmons–Smith cyclopropanation route and systematically investigated for its thermal degradation behavior and decomposition kinetics. Comprehensive spectroscopic and chromatographic characterization using FTIR, NMR, GC–FID, and GC–MS/MS confirmed the successful incorporation of cyclopropane moieties. The synthesized fuel exhibited a density of 0.894 g mL −1 , net heat of combustion (NHOC) of 43.62 MJ kg −1 , kinematic viscosity of 7.55 mm 2 s −1 at −20 °C, and a flash point of 49.3 °C, indicating its suitability for HED fuel applications. Thermal degradation behavior was investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Decomposition kinetics were evaluated using the Kissinger and Friedman methods, yielding activation energies of 80.88 and 81.65 ± 0.42 kJ mol −1 , respectively. GC–MS/MS analysis of thermal degradation products revealed the formation of predominantly aromatic hydrocarbons, indicating hydrocarbon‐dominated degradation pathways. To the best of our knowledge, this is the first report describing the thermal degradation behavior, decomposition kinetics, and degradation product distribution of CPBP.
Determining internal stresses in cylindrical lithium‐ion batteries is crucial when silicon‐based particles are added to the porous anode coating (PAC). A reliable homogenized constitutive model must be developed to capture both out‐of‐plane and in‐plane mechanical properties of the PAC to perform efficient cell‐level mechanical simulations where particle‐resolved approaches are computationally impractical. We propose a complete, balanced, and cost‐effective workflow designed for practical engineering applications. Out‐of‐plane properties are characterized by microindentation (MI) experiments, while a particle‐resolved simulation‐based design of experiments (DoE) serves as an efficient tool to determine the bulk in‐plane behavior. Simulations indicate an effective Poisson’s ratio of the PAC bulk in a range from 0.2 to 0.39, which contradicts the zero Poisson’s ratio assumption in existing literature. Finally, these results are used to parameterize porous elastic and Drucker‐Prager Cap (DPC) plastic models to estimate swelling stresses under fully constrained conditions. The model predicts out‐of‐plane stresses of 2.5–3.5 MPa and in‐plane stresses of 1.5–2.5 MPa at 10% macroscopic swelling of the PAC, which align with empirical literature data. The proposed workflow demonstrates a highly balanced and readily deployable engineering methodology for a mechanical analysis on a cell level.
The development of efficient electrode materials through simple and scalable synthesis routes is essential for advancing high‐performance supercapacitors. Here, we report the synthesis of a tungsten oxide‐tungsten disulfide (WO 3 /WS 2 ) composite material using a facile one‐pot hydrothermal method. The coexistence of WO 3 and WS 2 materials is confirmed using TEM, XRD, XPS, and Raman spectroscopy. In the composite, the WS 2 layers provide mechanical stability and high conductivity, whereas WO 3 nanoparticles enhance the capacitance significantly through pseudocapacitive charge storage. The electrochemical measurements in a three‐electrode system with 1 M H 2 SO 4 electrolyte delivered a specific capacitance of 578.7 F/g at 1 A/g. A symmetric supercapacitor device fabricated with the composite presented an energy density of 10 Wh/kg at a power density of 800 W/kg, with nearly 100% capacitance retention after 10,000 cycles.
Methanol oxidation reaction (MOR) is getting research attention as an alternative to the oxygen evolution reaction (OER) due to its fast reaction and low required potential. Herein, hydrotalcite‐derived Ni–Al mixed metal oxides with intended molar ratios of 0.8/0.2, 0.6/0.6, and 0.8/0.4 are prepared for MOR applications. The catalysts were fully physico‐chemically characterized regarding their structure, texture, and redox properties. The materials showed high surface area and were active for MOR. However, among the as‐prepared catalysts, the material with high NiO dispersion showed an excellent response for MOR. In an optimized electrolyte of 1 M KOH and 2 M methanol, the best catalyst achieved a maximum current density of 32.35 mA cm −2 , at an overpotential of 0.7 V versus Ag/AgCl, with a Tafel slope of 36.8 mV dec −1 . The catalyst also exhibited an electrochemically active surface area (ESCA) of 0.552 cm 2 and stability of 5000 s. The excellent electrocatalytic performance of the Ni 0.8 Al 0.2 ‐O x catalyst demonstrates that the hydrotalcite‐derived Ni–Al mixed oxides have the potential to be one of the cost‐effective and efficient electrocatalysts for methanol oxidation.
Phase change cooling technology, as a cold chain transportation strategy for maintaining low‐temperature environments and effectively ensuring food quality, has been widely adopted owing to its advantages of high energy storage density and cost‐effectiveness. However, material leakage during phase change reduces cooling capacity and risks product contamination. This study introduces a leak‐free composite phase change hydrogel (CPCG) with stable structural properties for food cold chains. The gel demonstrates high enthalpy (153.7 J/g) and thermal conductivity (0.5614 W·m −1 ·K −1 ) and stable cooling capacity release near −20 °C, enabling efficient cold energy utilization. Two preparation methods were compared: physical cross‐linking with thickeners versus chemical cross‐linking via covalent bonds. Leakage prevention tests and thermal performance analysis revealed that chemically cross‐linked gels exhibit excellent morphological stability, zero leakage, and near 100% mass retention. This material also exhibits exceptional dimensional flexibility. Compression and tensile tests demonstrate its outstanding compressive modulus (47.3 kPa), favorable tensile modulus (16.6 kPa), and bending ductility (capable of 360° folding without fracture), thereby preventing structural damage during handling. The results of the cycle stability test show that after 100 thermal cycles, the latent heat loss of the gel is small (with a decay rate of only 13.5%), demonstrating excellent cycle stability.
