Due to the strong effect of the composite fabrication method on the structural capacitor performance, the structure development should be performed with the involvement of composite engineers. Structural development should be conducted with inclusion of the electrical contacts in the overall design.
High-field and energy-density capacitors have gained substantial attention from academics and industry, particularly for power electronics, where they will play a key role in optimising the performance of management systems in electric vehicles.
The technical challenges relate to the capacitor development, structure development, and application development. Concerning the dielectric capacitor development, the dielectric material can be improved in terms of increasing the permittivity, decreasing the energy loss, and increasing the dielectric strength.
The production of electric field results due to the insulating nature of the dielectric material keeping the charges separated, which allows the capacitor to store energy.
In dielectric capacitors, an external electric field is applied to induce polarisation in the dielectric, allowing for the storage of electrical energy (Fig. 4a). When the electric field is removed, the capacitor releases the stored energy, and the dipoles return to their initial state (Fig. 4b).
Since service life and safety are essential for structural capacitors, dielectric structural capacitors are more promising than structural supercapacitors, in spite of the fact that the capacity for small-scale energy storage tends to be greater for a supercapacitor than a dielectric capacitor.