To optimize the utilization of thermal conversion systems, it is essential to integrate them with thermal energy storage. Among many types of base materials, the phase change materials are the most satisfactory mediums to store and release the thermal energy due to their high latent heat of fusion. In general, the phase change materials have low thermal conductivity. Nanoadditives have been investigated to further enhance the thermal properties of the phase change materials. This paper reviews the research development of the various types of phase change materials, nanoadditives, nanofluids, and nanocomposites as possible materials for efficient thermal energy storage. Some deficit in the literature has been noticed on the dispersion of various types of nanoparticles in the various types of base materials. It is also recommended that further studies are required to understand the stability of the nanofluids and nanocomposites due to a large number of thermal cycles.