A unique core–shell structured ZnO/NiO heterojunction to improve the performance of supercapacitors produced using a chemical bath deposition approach

Abstract

The integration of metal oxide composite nanostructure has attracted great attention in supercapacitors (SCs) applications. Herein, we have fabricated a series of various metal oxide composite nanostructures, such as ZnO...

Enhanced-Performance Asymmetric Supercapacitor Based on a Multidimensional Hierarchically Assembled NiMoO4/ZnMoO4/NF Electrode

“…The diffraction peaks at 13.22, 19.47, and 24.18° correspond to the (−110), (020), and (120) planes of ZnMoO 4 (JCPDS: 35-0765), respectively, and other diffraction peaks located at 23.36, 26.58, 28.47, 32.14, 33.74, 36.91, 38.95, 40.34, 47.55, and 53.92° correspond to the (02–1), (220), (31–1), (112), (22–2), (400), (040), (330), (421), and (53–1) planes of NiMoO 4 (JCPDS: 45-0142), confirming the successful preparation of NZMO/NF at 450 and 500 °C. ,, Figure b shows the XRD patterns for the samples obtained without introducing Zn 2+ and Ni 2+ , respectively. When Ni 2+ was not added (blue line), the diffraction peaks at 31.77, 34.42, 36.25, 47.54, 56.60, 62.86, and 67.96° belonged to the (100), (002), (101), (102), (110), (103), and (112) planes of ZnO (JCPDS: 36-1451); no diffraction peaks of ZnMoO 4 were found . The peak of the sample without Zn 2+ at 2θ = 28.82° corresponds to the (220) crystal plane of NiMoO 4 (JCPDS: 33-0948 (black line)) .…”

“…When Ni 2+ was not added (blue line), the diffraction peaks at 31.77, 34.42, 36.25, 47.54, 56.60, 62.86, and 67.96°belonged to the (100), ( 002), ( 101), ( 102), ( 110), (103), and (112) planes of ZnO (JCPDS: 36-1451); no diffraction peaks of ZnMoO 4 were found. 18 The peak of the sample without Zn 2+ at 2θ = 28.82°corresponds to the (220) crystal plane of NiMoO 4 (JCPDS: 33-0948 (black line)). 19 Diffraction peaks of ZnMoO 20 In the XPS spectra of Ni 2p (Figure 2b) for NiMoO 4 /NF and NZMO/NF, the Ni 2p spectrum is mainly composed of two main peaks (Ni 2p 1/2 (872.9 eV) and Ni 2p 3/2 (855.2 eV)) and two satellite peaks (879.7 and 861.3 eV), in which the fitting peaks match with Ni 3+ and Ni 2+ .…”

Transition Metal Oxide Electrode Materials for Supercapacitors: A Review of Recent Developments

“…As supercapacitor electrodes, the GNCs exhibit great capacitance of 194 F g −1 at 20 A g −1 (277 F g −1 at 0.05 A g −1 ) and capacitance loss of 2.6% after 15,000 cycles. Chebrolu et al [ 146 ] fabricated a series of metal oxide composite nanostructures using the chemical bath deposition method. Those metal oxide composite nanostructures include ZnO nanowires, NiO nanosheets, ZnO/CuO nanowire arrays, ZnO/FeO nanocrystals, ZnO/NiO nanosheets, and ZnO/PbO nanotubes, among which ZnO/NiO nanosheets have the best electrochemical performance (at 8 mA cm −2 with a specific capacitance of 1248 F g −1 and long-term cycling stability).…”

Critical Aspects of Various Techniques for Synthesizing Metal Oxides and Fabricating Their Composite-Based Supercapacitor Electrodes: A Review

“…The ZnO/NiO nanosheets exhibited the highest pseudocapacitive specific capacitance of 1248 F g −1 and the best cycling stability (79%) of all the electrodes after 3000 cycles. The simple CBD method and the synergistic contributions of the n -type ZnO and p -type NiO improved the electrochemical performance of the electrode [ 148 ]. However, the electrode materials exhibited low energy densities, which limited their industrial applications to advanced multifunctional SCs.…”