Composite structural supercapacitors (SSC) are an attractive technology for aerospace vehicles; however, maintaining strength whilst adding energy storage to composite structures has been difficult. Here, SSCs were manufactured using aerospace-grade composite materials and CNT mat electrodes. A new design methodology was explored where the supercapacitor electrolyte was localised within the composite structure, achieving good electrochemical performance within the active region, whilst maintaining excellent mechanical performance elsewhere. The morphologies of these localised SSC designs were characterised with synchrotron X-ray fluorescence microscopy and synchrotron X-ray micro-computed tomography and could be directly correlated with both electrochemical and mechanical performance. One configuration used an ionogel with an ionic liquid (IL) electrolyte, which assisted localisation and achieved 2640 mW h kg⁻¹ at 8.37 W kg⁻¹ with a corresponding short beam shear (SBS) strength of 71.5 MPa in the active area. A separate configuration with only IL electrolyte achieved 758 mW h kg⁻¹ at 7.87 W kg⁻¹ with SBS strength of 106 MPa in the active area. Both configurations provide a combined energy and strength superior to results previously reported in the literature for composite SSCs.

Vanadium dioxide (VO₂) has been identified as a material capable of transitioning from an insulator to a metal close to room temperature. Previous works have demonstrated potential applications of this material in various microwave components or devices. However, the complex permittivity and permeability characterization of the VO₂ over X-band has not been previously reported. Knowledge of these properties is essential for accurate modeling of the components and devices utilizing VO₂. This paper characterizes a VO₂ film deposited on a quartz substrate in a WR90 waveguide using a vector network analyzer. The S-parameters, conductivity, relative complex permittivity, and permeability of the VO₂ film are determined across the transition temperature.

Exposure to plasma can significantly increase the surface area of silver species and their resistance to oxidation. While some work investigating plasma-treated silver has been done, limited morphologies and applications have been explored. We hereby explore this effect on silver nanowires (AgNWs) through medium-vacuum air plasma exposure time ranging between 30 s to 60 min. These plasma-treated AgNW networks are directly applied as supercapacitor electrodes, without any carbon or polymer additives that are typically employed alongside silver in energy storage applications. The plasma treatment consequently affected the electrochemical performance of AgNWs, where longer treatment times resulted in higher energy storage capacity. An increase in resistance was observed for plasma treatment times greater than or equal to 5 min, due to the switch from the percolation threshold of the metallic Ag phase to the Ag₂O phase. Despite an initial drop in stored energy, an overall improvement in energy storage capacity was observed throughout cycling, where the optimal plasma treatment time of 5 min resulted in an increase of 320% of its starting value with near 100% coulombic efficiency, through the development of stable redox-active surface nanostructures.

Carbon fiber reinforced polymer (CFRP) materials are anisotropic lossy conductors which restrict their use in high-performance lightweight and load-bearing waveguides. The attenuation of CFRP waveguides has been improved in this research by investigating and comparing three different manufacturing techniques. WR-90 waveguides have been manufactured from Cytec IM7/977–3 prepreg and their transmission performance was evaluated. Three different techniques were implemented to reduce waveguide losses including: copper foil lining, conductive paint, and a new integrated metalized carbon fiber veil (CFV) material. The new lightweight high conductivity CFV was integrated into the walls of a CFRP waveguide which reduced the per unit length attenuation to below 1 dB/m. This was an improvement of up to 5.5 dB over raw carbon fiber and similar to the performance of a copper foil-lined waveguide.