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This work describes the development of a woven carbon fiber and thermoset polyester resin based structural supercapacitor via three-dimensional (3D) printing. The specific surface area and capacitance of the electrodes were increased by hydrothermally synthesized N-doped Zn-Co selenide nanowires on the surface. The supercapacitor with N@ZnCoSe 2 -MXene exhibited an energy of 2.69 Wh kg −1 , a power density of 43.20 W kg −1 , and a Coulombic efficiency of 88.8% at 1000 mA g −1 of current density. The cyclic stability and multifunctionality of the device were satisfactory, and the capacitance retention was 83.7% at the same current density after 6000 consecutive charge−discharge cycles. The device's high tensile strength (637.679 MPa) and modulus (36.92 GPa), with an impact energy absorption capacity of 2.22 J g −1 , indicated its mechanical robustness. The device exhibits a comparable performance under various weather conditions. It retains 39.11 F g

We report a study on manufacturing and characterization of a platform material for high-performance lightweight bipolar plates for fuel cells based on nanocomposites consisting of carbon nanotubes (CNTs) and exfoliated graphite nanoplatelets (xGnPs). The experiments were designed and performed in three steps. In the preexperimental stage, xGnP-epoxy composite samples were prepared at various xGnP weight percentages to determine the maximum processable nanofiller concentration. The main part of the experiment employed the statistics-based design of experiments (DOE) methodology to identify improved processing conditions and CNT : xGnP ratio for minimized electrical resistivity. In the postexperimental stage, optimized combinations of material and processing parameters were investigated. With the aid of a reactive diluent, 20 wt.% was determined to the be maximum processable carbon nanomaterial content in the epoxy. The DOE analyses revealed that the CNT : xGnP ratio is the most dominant factor that governs the electrical properties, and its implications in relation to CNT-xGnP interactions and microstructure are elucidated. In addition, samples fabricated near the optimized condition revealed that there exists an optimal CNT : xGnP ratio at which the electrical performance can be maximized. The electrical and mechanical properties of optimal samples suggest that CNT-xGnP hybrid nanocomposites can serve as an alternative material platform for affordable, lightweight bipolar plates.

In this study, a carbon nanotube-glass bubble/polyamide 6 (CNT-GB/PA6) multiscale hybrid composite was manufactured. Through a coagulation process including CNT and GB, a segregated network was formed to produce a composite structure with tunable thermal conductivity. Within the segregated network structure, a complex phenomenon of decrease and increase in thermal conductivity owing to the interaction by CNT and GB, and an equation to predict thermal conductivity through the contents of GB and CNT was formulated. A model to predict the thermal conductivity using the RSM analysis was presented, and the contents of GB and CNT were adjusted according to the required thermal conductivity. It was confirmed through the LFA thermal conductivity measurement that the thermal conductivity increased with GB and CNT contents. Moreover, when 30% of GB was added to the 5 wt% CNT composite, the thermal conductivity increased by about 17%. However, in the experiment to confirm the effect of GB alone, it was confirmed that the thermal conductivity decreased as the GB content increased. Thus, the size of the structural path, which was controlled by the GB content through which electrons pass, played an important role in this study. The results of this study can be used in astronautic fields that require insulation to save energy and in construction engineering where thermal insulation and heat emission are important.

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This paper aims to improve the accuracy of the finite element analysis for the preform shape transformation according to the difference in the type of carbon fiber and friction force. The carbon fiber type (Toray T700, Zoltek), the fiber direction (0°/90°, ± 45°), and the frictional force were measured, which occurred between the fiber and the mold and between the fiber and the fiber. A comparative experiment was conducted through actual preform production by designating it as a variable for element analysis. The analysis was conducted according to the difference between the static friction coefficient and the dynamic friction coefficient in the molding analysis. Within the range of the Coulomb equation, the shear angle changing was compared with the actual preform shape to show similar results.