The perovskite Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) is considered to be the most promising ideal SOFC cathode due to its outstanding catalytic activity for the oxygen reduction process and high mixed electrical and ionic conductivity. To take advantage of the ionic conductivity and electrocatalytic capabilities of BSCF, by mixing the traditional electrolyte yttrium-stabilized zirconia (YSZ) with the functional electrolyte BSCF to generate a composite semiconductor-ionic conductor, we were able to effectively complete the first use of BSCF as a functional electrolyte. The distinctive BSCF–YSZ composite produced a fuel cell performance of 743 mW/cm² at 550 °C and even an exceptional fuel cell performance of 302 mW/cm² at 450 °C by adjusting the YSZ concentration. The ionic conductivity was greatly increased in the composite samples by rapid conduction over the interface, according to electrochemical and electrical analyses. This research introduces a fresh approach to the creation and use of BSCF materials as well as the creation of novel electrolytes for LT-SOFC.