Core–shell (CS) structure is generally named when the structure has two distinct materials or characteristics in which one acts as core, which is inner material, and the other one as shell, which is an outer layer on core. Heterogeneous CS nanostructures are found interesting for electrochemical supercapacitor (SC) applications, as they could provide more electroactive locations, good electrons/ions transport, better electronic conductivity, improved stability, and other synergetic effects arising from the combination of two different materials as core and shell. The development of these CS structures could be controlled through various synthesis parameters such as precursor materials, the addition of reagents or surfactants, and experimental parameters during or post-synthesis. The unstable core materials could also be stabilized by selecting suitable shell materials, and the form of CS nanostructures could improve their physicochemical properties along with their multifunctional characteristics. Various forms of CS nanostructures were developed for high-performance SCs with combinations of metal, metal oxide (MO), organic materials, polymers, etc. This chapter deals with different types of CS materials with distinct CS nanostructures and their potential utilization for high-performance SCs.