Thermoelectric (TE) materials offer significant potential in waste heat energy harvesting because of their ability to convert heat into electricity using the principle of the Seebeck effect. TE device has no moving parts, free of noise, and has a longer lifetime. In the mid-temperature range (400–850 K), Co4Sb12 skutterudite-based materials exhibit one of the highest energy conversion efficiencies. A critical factor that affects the conversion efficiency is the thermoelectric figure of merit, defined as zT=(S^2 T)⁄ρκ, where S denotes the Seebeck coefficient, ρ denotes the electrical resistivity, T denotes the absolute temperature, and κ denotes the total thermal conductivity. The total thermal conductivity is the contribution of the electronic thermal conductivity (κe) and lattice thermal conductivity (κl). The filled skutterudites with the general structural-chemical formula MyCo4Sb12, where the “filler atom” M occupies the voids of the skutterudite lattice. Due to the abundance of Co and Sb, its thermal stability, and comparatively better electronic properties, Co4Sb12-skutterudites are promising TE materials in the temperature range of 450 - 750K. It is reported that the figure of merit > 1.5 is achieved only in multiple rare-earth-filled skutterudites. Nevertheless, the multiple filling may make the TE material system more complex and non-reproducible for practical applications. In addition, the availability of RE elements is scarce nowadays. To avoid the multiple rare-earth elements filling and to obtain high-efficient skutterudites, in the present work, single-filled skutterudites have been processed using the powder metallurgy route. It is observed that Ni-doping at the Co site enhances the TE properties of single-filled skutterudites through improved charge carrier concentration at the Fermi level and enhanced phonon scattering by creating Ni-rich grain boundaries. The strategy to enhance the thermoelectric properties of both n-type and p-type skutterudites through band engineering and nanostructuring will be explored. Further, a thermoelectric prototype using indigenous n-type and p-type skutterudite legs with proper electrode/thermoelectric joints will be designed, fabricated, and demonstrated.