2. Carbon Nanomaterials in Renewable Energy Production and Storage Applications

With the increase in worldwide consumption of nonrenewable energy resources (i.e., fossil fuels) and emission of toxic gases, it is our foremost concern to concentrate our research on sustainable and renewable energy. This motive paved the way to develop several renewable energy production and storage systems, like solar cells, supercapacitors, fuel cells, and lithium-ion batteries. These devices, with high specific power, long cycle life, portability, and ease of fabrication, have been able to secure worthy positions in the field of energy science and technology. Over the last decades, attempts have been taken to use nanostructured carbon-based materials, like graphene and carbon nanotubes (CNTs), with the aim of improving the efficiency of the abovementioned energy storage systems.

In this book chapter, focus has been directed toward the recent progress and advancement on the efficiency of the electrode materials of these renewable energy storage systems via application of CNTs, graphene, or nanohybrid fillers. The ability of these materials to exhibit superior capacity toward photon absorption, capability toward generation of photocarriers, photovoltaic properties, and separation of charge carriers to form heterojunctions makes them ideal applicants in solar cells. The capacitance of a supercapacitor varied with the specific surface area, synthetic approach, pore size, pore size distribution, and posttreatment of these materials. Moreover, high electron conductivity and high surface area of these nanomaterials led to improvements in (a) electrode reaction rates in fuel cells, lithium-ion batteries, and supercapacitors and (b) charge storage capability of supercapacitors and lithium-ion batteries.