Hybrid graphene and carbon nanotube–reinforced composites: polymer, metal, and ceramic matrices

Graphene and carbon nanotube (CNT) have been recognized as the new-generation and state-of-the-art nano-reinforcement for polymers, metals, and ceramics as a function of their unique nanostructures, extraordinary mechanical properties, and outstanding multifunctional features. Despite the advantages, however, recently, there have been some concerns about the challenges associated with the use of graphene and CNT as nano-reinforcement in composites, i.e., poor dispersion in the host matrix, the anisotropic electrical/thermal properties, limiting the further improvement of graphene or CNT-reinforced materials. Very recently, hybridization of graphene and CNT was reported to solve the above issues in case of single graphene or CNT as reinforcement. Herein, we commence our review by giving a general preface on the impact of materials on human development and the role of graphene/CNT hybrid in maximizing the performance of materials. Then, given the importance of the availability of graphene/CNT hybrid, we proceed with a specific discussion on the strategies and simulations for the hybridization of graphene with CNT. Subsequently, we concentrate our attention on state-of-the-art graphene/CNT hybrid–reinforced polymer, metal, and ceramic matrix composites, respectively, critically showcasing the progress and associated mechanisms of three-dimensional carbonaceous nanofillers within various matrices. Finally, we provide perspectives on practical technological limitations/challenges and emerging opportunities for advanced composites.