Abstract: | We have synthesized and characterized perovskite‐type SrCo0.9Nb0.1O3?δ (SCN) as a novel anion‐intercalated electrode material for supercapacitors in an aqueous KOH electrolyte, demonstrating a very high volumetric capacitance of about 2034.6 F cm?3 (and gravimetric capacitance of ca. 773.6 F g?1) at a current density of 0.5 A g?1 while maintaining excellent cycling stability with a capacity retention of 95.7 % after 3000 cycles. When coupled with an activated carbon (AC) electrode, the SCN/AC asymmetric supercapacitor delivered a specific energy density as high as 37.6 Wh kg?1 with robust long‐term stability. |