Electrification, including emerging technologies such as structural supercapacitors, is critical in realizing carbon-neutral transportation. A fundamental challenge is the trade-off between mechanical properties and energy storage capabilities. We report the fabrication of structural supercapacitors with a novel fibre-fibre interface to improve the interlaminar strength and encapsulation while considering the effect of structural resin on energy storage performance. The synthesized graphene nanoplatelets-modified electrodes attain a high specific surface area of ∼231 m² g⁻¹ - outperforming comparable carbon-based electrodes. We learned that the use of a gel-polymer electrolyte (GPE) separator containing 60 wt% Li-salt eliminates the requirement of electrolyte infusion and showed the highest values for conductivity for the cell produced using GPE. The implementation of glass fabrics (GFs) into the GPE improved the flexural modulus by ∼22%, while retaining the mechanical strength of the cells. The multifunctional performance of the produced SSCs were on par or even outperformed the performances of SSCs reported in literature. A proof-of-concept prototype demonstrates that gel-polymer electrolyte cells can retain charges for longer than those with a glass fibre separator. Cumulatively, these offer the possibility of conventional composite manufacturing techniques to scale-up and eliminate delamination issues arising from different thermal expansion coefficients which also addresses the balance between mechanical stability and electrochemical performance. Our findings support the advancement of durable, lightweight energy storage and delivery systems for sustainable transportation, with potential applications in robotics and wearable technologies.

The twist-bend nematic (N _tb) phase is a recent addition to the family of nematic (N) phases of liquid crystals (LCs). A net polar order in the N _tb phase under an external electric field is interesting and it was predicted in several recent theoretical studies. We investigated the field-induced polarization behaviour, dielectric, and electro-optic properties of a bent LC dimer CB7CB in the N and N _tb phases. A threshold-dependent polarization current response was obtained in both the phases under triangular and square-wave input electric fields, existing till frequencies as high as 150 Hz. The polarization switching times were found in ∼1 ms region, especially in the N phase. In the N _tb phase, electric field-induced deformation of the helical structure was observed, like ferroelectric LCs. Dielectric measurements revealed the presence of cybotactic clusters via collective relaxations. The dielectric anisotropy (Δϵ) is negative at the frequencies of polarization measurements. The net polarization resulted from field-induced reorientation of cybotactic clusters and additionally from the field-induced deformation of helical structures in the N _tb phase. We explored the possibility of ionic contributions to the net polarization by synthesizing TiO ₂ nanoparticles (NPs) dispersed CB7CB LC nanocomposite. Incorporation of the NPs resulted in reduction of the collective order, increase in the ionic impurity content and conductivity, but an extinction of the field-induced polarization response. Our results demonstrate that the net polarization has competing contributions from both ferroelectric-like and ionic origin (up to ∼10 Hz) in the LC phases, but it becomes dominantly ferroelectric-like at higher frequencies.

We study a quantum-dots (QDs) dispersed bent-core nematic liquid crystalline system in planar geometry and present experimental measurements of the birefringence (Δn), order parameter (S), dielectric dispersion, absorption spectra, and optical textures with attention to variations with temperature. A bent-core liquid crystal (LC) 14-2M-CH3 is used as the host material and CdSe/ZnS core-shell type QDs are used as the dopant. The nematic (N) phase of the pristine (undoped) LC 14-2M-CH3 contains cybotactic clusters, which are retained by its QDs incorporated LC nanocomposite. Our experimental findings support: (i) reduced orientational order parameter of the QDs dispersed LC system compared to its pristine counterpart at fixed temperatures, (ii) reduced cybotactic cluster sizes due to the incorporation of QDs, and (iii) increased activation energies related to reduced cluster sizes. We complement the experiments with a novel Landau-de Gennes-type free energy for a doped bent-core LC system that qualitatively captures the doping-induced reduced order parameter and its dependence on the properties of the QDs and its variation with temperature.