<p>This study investigates the functional properties of NdBa_1–xCa_xMn₂O_6–δ solid solution for application as oxygen storage materials. The synthesised oxides demonstrated elevated phase purity and structural stability, as evidenced by XRD analysis. The solubility limit of calcium was determined to be x ≥ 0.2, beyond which the structural integrity was maintained. Thermogravimetric analysis revealed an oxygen capacity of up to 4% at 700&#xa0;°C, indicating the potential of these materials for application in airless combustion of hydrocarbons. Such a process would align with modern ecological requirements. Coulometric titration measurements of the oxygen content in the calcium doped oxide revealed the existence of two stable phases with reversible oxygen exchange. A defect formation model was developed on the basis of experimental data, with manganese redox reactions and oxygen vacancy formation identified as the dominant mechanisms governing oxygen storage. Calcium substitution has been demonstrated to facilitate defect formation at near-atmospheric oxygen partial pressures. Cyclic tests have confirmed that NdBa_0.8Ca_0.2Mn₂O_6–δ exhibits both the highest oxygen storage capacity and exceptional cycling stability when compared to its calcium-free counterpart. The collective experimental results and subsequent analysis position calcium doping as a promising strategy for designing double manganites with advanced oxygen storage capabilities.</p>