An Effective Electrodeposition Mode for Porous MnO(2)/Ni Foam Composite for Asymmetric Supercapacitors

Three kinds of MnO(2)/Ni foam composite electrode with hierarchical meso-macroporous structures were prepared using potentiodynamic (PD), potentiostatic (PS), and a combination of PS and PD(PS + PD) modes of electrodeposition. The electrodeposition mode markedly influenced the surface morphological, textural, and supercapacitive properties of the MnO(2)/Ni electrodes. The supercapacitive performance of the MnO(2)/Ni electrode obtained via PS + PD(PS + PD(MnO(2)/Ni)) was found to be superior to those of MnO(2)/Ni electrodes obtained via PD and PS, respectively. Moreover, an asymmetric supercapacitor device, activated carbon (AC)/PS + PD(MnO(2)/Ni), utilizing PS + PD(MnO(2)/Ni) as a positive electrode and AC as a negative electrode, was fabricated. The device exhibited an energy density of 7.7 Wh·kg(−1) at a power density of 600 W·kg(−1) and superior cycling stability, retaining 98% of its initial capacity after 10,000 cycles. The good supercapacitive performance and excellent stability of the AC/PS + PD(MnO(2)/Ni) device can be ascribed to its high surface area, hierarchical structure, and interconnected three-dimensional reticular configuration of the nickel metal support, which facilitates electrolyte ion intercalation and deintercalation at the electrode/electrolyte interface and mitigates volume change during repeated charge/discharge cycling. These results demonstrate the great potential of the combination of PS and PD modes for MnO(2) electrodeposition for the development of high-performance electrodes for supercapacitors.