Promising energy conversion devices, reversible solid oxide cells (R-SOCs) offer the potential for the efficient conversion of fuel into electrical energy. Nonetheless, the development of a reliable bifunctional electrocatalyst as an electrode material for R-SOC devices presents considerable challenges. Hence, two semiconductors, Ba 0.9 Co 0.2 Fe 0.7 Nb 0.1 O 3−δ (BCFeN) and Ba 0.9 Co 0.2 Fe 0.7 Nb 0.1 F 0.1 O 2.9−δ (BCFeNF) are synthesized. F doping causes a significant reduction in the average valence states of Co, Fe, and Nb elements, ultimately leading to a rise in the concentration of oxygen vacancies, further enhancing the oxygen migration capability of BCFeN. Furthermore, F doping enhances the catalytic performance for the oxidation of hydrogen and the reduction of oxygen. The rate-determining step (RDS) in hydrogen oxidation reaction on BCFeN and BCFeNF surfaces is the H 2 adsorption and dissociation process, while the RDS in oxygen reduction reaction is the reduction of adsorbed oxygen atoms to O − species. Remarkably, the outstanding reversible performance is exhibited by the single cell employing BCFeNF with O 2 as the oxidant and humidified H 2 (30% H 2 O) as the fuel. At 700 °C, when operating in solid oxide fuel cell mode, the maximum power density reaches 288.9 mW cm −2 , and the R-SOC maintains a current density of −301.6 mA cm −2 at 1.3 V in solid oxide electrolysis cell mode.