Solid oxide fuel cells (SOFCs) have attracted a great deal of consideration among the promising fuel cell systems for energy conversion. In SOFC, electrolyte plays a vital role to increase the energy conversion efficiency. The main hurdle is its higher operating temperature (1000°C) which results in design limitation and higher fabrication cost. In this work, Gadolinium Doped barium cerate (BCG) composite electrolyte was successfully synthesized to operate at intermediate temperature (600–800°C) by co-precipitation technique. The structure of BCG was identified as orthorhombic perovskite and the crystallite size was found to be around 30 nm. From TEM, the particle size was found to be 32nm and is in good agreement with XRD results. Further, the particles sizes were found to be uniform in size and shape. From the above results it is understood that the obtained particle is a single crystallite which indicates the absence of agglomeration. The formations of BCG nanoparticles were resulted in reduced sintering temperature of the electrolyte. By lowering the sintering temperature, the barium loss was successfully reduced in order to get the required orthorhombic perovskite phase. The lower activation energy was found for BCG composite electrolyte, which can acts as a best electrolyte for at intermediate temperature applications.