A review of morphological, structural, dielectric, and electrical properties of renewable plant-based dielectric composite materials

The growing demand for sustainable alternatives to petroleum-based materials has accelerated the development of renewable plant-based dielectric composites. These materials offer an effective balance between environmental benefits and functional performance for electronic and energy applications. This review synthesizes recent studies on the morphological and structural characteristics of plant-based composites, including particle size, surface roughness, porosity, and polarity, and examines how these attributes influence dielectric and electrical properties. Emphasis is placed on materials derived from cellulose, lignin, agricultural residues, and plant oils with structural insights obtained primarily through scanning electron microscopy (SEM). Comparative dielectric parameters from selected works are compiled to explain how morphological tuning and processing methods affect permittivity, loss tangent, and conductivity. By identifying important structure–property relationships, this review provides practical guidance on material selection, processing optimization, and suitability for specific applications. Unlike earlier reviews that addressed dielectric properties or material classifications in isolation, this work integrates morphology, structure, and dielectric or electrical behavior within a unified framework. The review concludes with recommendations for experimental design, compatibility evaluation, and future research directions to support the sustainable development of plant-based dielectric composite materials for next-generation systems.