Because of their various nanostructures, carbon nanotubes (CNTs) and graphene have garnered considerable attention, making it a particularly appealing and broad topic in nanotechnology. Graphene and carbon nanotubes (CNTs) both have unique electrical, mechanical, thermal, catalytic, and electrochemical features because they are made up of sp2 hybridized carbon atoms. Carbon nanotube hybrid nanostructured materials (CNT hybrid nanocomposites), Carbon nanotubes (CNTs), and nanotechnology have the potential to improve energy conversion and storage device applications. Carbon nanotubes are being evaluated for application in renewable energy sources, including solar cells and hydrogen storage. Carbon nanotubes (CNTs) are utilized in storage technologies such as Li-ion batteries, supercapacitors, and thermal energy harvesting.