Abstract
Three kinds of MnO2/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 MnO2/Ni electrodes. The supercapacitive performance of the MnO2/Ni electrode obtained via PS + PD(PS + PD(MnO2/Ni)) was found to be superior to those of MnO2/Ni electrodes obtained via PD and PS, respectively. Moreover, an asymmetric supercapacitor device, activated carbon (AC)/PS + PD(MnO2/Ni), utilizing PS + PD(MnO2/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(MnO2/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 MnO2 electrodeposition for the development of high-performance electrodes for supercapacitors.
Highlights
There is increasing demand for electrical energy storage for hybrid electric vehicles, uninterruptible power supplies, and mobile electronic devices
No distinct diffraction peaks of MnO2 were observed in the X-ray diffraction (XRD) patterns; only those corresponding to the Ni foam substrate appeared
PS + PD(MnO2 /Ni) electrodes had a structure of interconnected macropores whose walls possess finer pores, which leads to increased mass transport through the former and high specific surface area due to the latter, giving it the highest specific capacitance among the three composite electrodes
Summary
There is increasing demand for electrical energy storage for hybrid electric vehicles, uninterruptible power supplies, and mobile electronic devices. Based on the pseudocapacitive energy storage mechanism, metal oxides/hydroxides, such as TiP2 O7 [11], NiO/RuO2 [12], LiTi2 (PO4 )3 [13], and Nb2 O5 [14], and metal nitrides MN (M = Cr, Co) [15], MgCo2 O4 [16], and Zn(OH)2 ́ –4Zn(OH)4 2 ́ [17] can provide higher specific capacitance than that provided by conventional carbon materials and better cycling. It is believed that an electrode with a porous structure and a high specific surface area is effective in enhancing the electrochemical properties of supercapacitors. In this study, nanostructured porous MnO2 /Ni foam composites were prepared via three electrodeposition modes and used as the positive electrode of an asymmetric supercapacitor. An asymmetric supercapacitor composed of a PS + PD(MnO2 /Ni) positive electrode and an activated carbon (AC) negative electrode was fabricated It exhibited a large specific capacitance, a high energy density, and excellent cycling performance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
