Insights into Interfacial Features of Metal/Eco-Composites Designed for Energy Storage

The development of innovative materials with improved properties is required for the field of energy storage. This article proves that it is possible to utilize bio-derived fillers to tune the performance of biodegradable polymers. For this scope, eco-composites were attained by loading several amounts of walnut leaf powder (WLP) in hydroxyethylcellulose (HEC). Basic testing was conducted to emphasize the sample's suitability for the pursued application. The rheological behavior was altered with the addition of WLP at low shear rates, which became more pseudoplastic, resulting in composite films with higher thickness uniformity. Wettability characteristics were used to analyze the macro-level adhesion of the platinum-containing samples, and the results showed that the presence of WLP led to the augmentation of interfacial compatibilization of the composite with the metal layer. The electron microscopy and atomic force microscopy scans showed the proper distribution of the WLP in the matrix. Local adhesion data derived from DFL-height curves further showed that the inclusion of WLP improves the adhesion capabilities at the nanoscale. The dielectric spectroscopy tests proved that the used biofiller leads to an enhancement in the permittivity of the composite with respect to the neat HEC. By accounting for all results, the generated eco-composites are suggested as alternative dielectrics for usage in the energy storage domain.