**1. Introduction**

Decades ago, scientists believed that carbon comes in two basic forms, that is, graphite and diamond, but in the last three decades, scientists have discovered new forms of carbon known as advanced carbon materials including fullerene, carbon nanotubes (CNTS), and graphene, respectively [1–6]. In recent years, graphene

is considered as an outstanding candidate for enhancing the structural, electrical, mechanical, and thermal properties of materials (for example, metals, ceramics, and polymers) [7, 8]. In hybrid nanostructures, the physical property enhancement may be possible due to excellent physical properties of the graphene. Excellent physical properties included higher thermal conductivity (5000 Wm−1 K−1), electrical conductivity (106 S m−1), and Young's modulus (1 TPa), which are a driving force for enhancement in the physical properties of hybrids. Among the various types of graphene materials, graphite oxide-derived graphene plays an important role in increasing the physical properties of hybrids because of its surface functionalization and its ability of large-scale production at any level. Even a tiny amount of graphene in hybrids (either polymers or ceramics or metals) may alter its physical properties to a great extent. In case of graphene, the compatible structural properties and how it makes bond with various types of nanostructures are reasons for improved properties in the end product (hybrids or composites). For example, reduced graphite oxide (rGO)-polystyrene composites with a low threshold content of 0.1 (volume %) rGO have shown greatly improved electrical conductivity (approx. 0.1 S m−1); this has been possible due to good dispersion of rGO in the polymer composite matrix. Similarly, in inorganic hybrids, rGO has been used for the deposition of Co3O4 particles for increased catalytic effects, which may have been used for the decomposition of ammonium perchlorate because of the complex properties of GO and Co3O4. In another research, rGO was used to improve the mechanical properties of the bulk silicon nitride (i.e. toughness is enhanced by up to 235%), which may be used for high-performance mechanical and structural applications [8, 9]. In short, graphene being the toughest, strongest, lightweight material may act as a wonder material for future scientific revolution in every aspect of life. Even if it is combined with polymers, metals, and ceramics, it may play a significant role in improving physical properties due to its versatile surface, morphology, chemistry, and physical properties. In this chapter, we will discuss graphene combination with various ceramics and how it has been used to improve their physical properties, and porous carbon for energy storage, respectively. This book chapter will be a significant contribution to advance studies on physical properties and technological applications.
