Co₃O₄ Exsolved Defective Layered Perovskite Oxide for Energy Storage Systems

We report a Co3O4 exsolved perovskite oxide PrBaMn1.7Co0.3O5+δ (Co3O4–PBMCO) that utilizes the Faradaic transfer of metal oxide and favorable OH– adsorption for an energy storage mechanism, as an active material for hybrid supercapacitors. It demonstrated electrochemical performances supported by both fast oxygen anion intercalation in the interior and Faradaic redox reaction on the surface of the active material, Co3O4–PBMCO. The flexible hybrid supercapacitor, Co3O4–PBMCO, coated onto the three-dimensional nickel wire (3D-Ni), exhibited outstanding capacitance (capacity) of 1571 F g–1 (218.54 mAh g−1), good rate capability, and cycle stability. With these performances, the hybrid device exhibited a high energy density of 215.80 Wh kg–1 and a power density of 1.48 kW kg–1, which are significantly higher than those of previously reported perovskite oxide-based electrodes. These results verified that our unique metal oxide exsolved layered perovskite oxide is a promising candidate as an active material for hybrid devices that can be widely applied for smart wearable and implantable devices.