The performance of allotrope carbon materials has been explored because of their superior properties in energy system applications. This review provides an understanding of the current work focusing on the applications of selected carbon materials in important energy systems, focus on thermal interface materials (TIMs), and fuel cell applications. This article begins with the introduction of TIMs and fuel cell in general working principle and presents details on carbon materials. The discussion focuses on updates from the latest research work and addresses current challenges and opportunities for research toward TIMs and fuel cell applications. The optimum performance of TIMs was seen when thermal conductivity achieved at a maximum of 3000 W (m K)(-1) by using vertically aligned carbon nanotubes (CNTs) and a minimum internal thermal resistance of 0.3 mm(2) K W-1. Meanwhile for fuel cell, the platinum/CNTs catalyst applied proton exchange membrane fuel cell achieved high power density of 661 mW cm(-2) in the presence of Nafion electrolyte membrane. This review provides insights for scientists about the use of carbon materials, especially in energy system applications.