Highly dense proton conducting materials of BCZYSZn (BaCe_0.8-xZr_xY_0.15Sm_0.05O_3-δ (x = 0.15, 0.20) with 4 wt.% ZnO as sintering additive), to be used as an intermediate temperature solid oxide fuel cells (IT-SOFCs) electrolyte, have been processed by the conventional solid state reaction method. The crystalline phase, microstructure, electrical properties, cell performance and chemical stability of the materials have been investigated. The ionic conductivity of BCZYSZn 3 (x = 0.20) material has been measured to be ~2.56 × 10^-3 S cm⁻¹ and ~8.32 × 10^-3 S cm⁻¹ at 600 °C and 850 °C, respectively in wet 5%H₂ in Ar atmosphere. Microstructural characterizations of the zinc containing materials (BCZYSZn) show the formation of highly dense morphology with very large grains. The chemical stability test of BCZYSZn in pure CO₂ shows that the material is very stable up to 1000 °C. The maximum power density for the BCZYSZn 3 electrolyte cell is found to be 0.42 W/cm² at 700 °C under the testing atmosphere. The performed characterizations reveal that these are suitable proton-conducting candidate materials for efficient electrochemical devices.