Unlocking supercapacitive energy storage potential: Catalyzing electrochemically inactive manganese oxides to active MnO2 via heterostructure reconstruction

Advancing supercapacitor system performance hinges on the innovation of novel electrode materials seamlessly integrated within distinct architectures. Herein, we introduce a direct approach for crafting nanorod arrays featuring crystalline/amorphous CuO/MnO2−x. This reconfigured heterostructure results in an elevated content of electrochemically active MnO2. The nanorod arrays serve as efficient capacitive anodes and are easily prepared via low-potential electrochemical activation. The resulting structure spontaneously forms a p–n heterojunction, developing a built-in electric field that dramatically facilitates the charge transport process. The intrinsic electric field, in conjunction with the crystalline/amorphous architecture, enables a large capacitance of 1.0 F·cm−2 at 1.0 mA·cm−2, an ultrahigh rate capability of approximately 85.4