Self-Supported Sheets-on-Wire CuO@Ni(OH)2/Zn(OH)2 Nanoarrays for High-Performance Flexible Quasi-Solid-State Supercapacitor

Abstract

Transition metal hydroxides have attracted a lot of attention as the electrode materials for supercapacitors owing to their relatively high theoretical capacity, low cost, and facile preparation methods. However, their low intrinsic conductivity deteriorates their high-rate performance and cycling stability. Here, self-supported sheets-on-wire CuO@Ni(OH)2/Zn(OH)2 (CuO@NiZn) composite nanowire arrays were successfully grown on copper foam. The CuO nanowire backbone provided enhanced structural stability and a highly efficient electron-conducting pathway from the active hydroxide nanosheets to the current collector. The resulting CuO@NiZn as the battery-type electrode for supercapacitor application delivered a high capacity of 306.2 mAh g−1 at a current density of 0.8 A g−1 and a very stable capacity of 195.1 mAh g−1 at 4 A g−1 for 10,000 charge–discharge cycles. Furthermore, a quasi-solid-state hybrid supercapacitor (qss HSC) was assembled with active carbon, exhibiting 125.3 mAh g−1 at 0.8 A g−1 and a capacity of 41.6 mAh g−1 at 4 A g−1 for 5000 charge–discharge cycles. Furthermore, the qss HSC was able to deliver a high energy density of about 116.0 Wh kg−1. Even at the highest power density of 7.8 kW kg−1, an energy density of 20.5 Wh kg−1 could still be obtained. Finally, 14 red light-emitting diodes were lit up by a single qss HSC at different bending states, showing good potential for flexible energy storage applications.

Unveiling the Mechanistic Significance of Reducibility and Lattice Oxygen Evolution in the Ce1–x–yZrxNiyO2−δ Catalyst for Methanol Electro-Oxidation

“…The Ni 2p spectra of both the as-prepared and exhausted catalysts exhibited distinct Ni 2p 3/2 and Ni 2p 1/2 components. The deconvoluted spectra confirmed the presence of Ni 2+ (855.1 and 872.5 eV) and Ni 3+ (857.1 and 874.2 eV) species. , Additionally, two satellite peaks were observed at higher binding energies of 861.3 and 865.3 eV Table reveals a gradual increase in Ni 3+ content from 22.4 to 49.7% with increasing Zr doping in the as-prepared catalysts.…”

“…In fact, the evolution of lattice oxygen enables CO oxidation, making the catalysts more tolerant to CO. 55,56 In order to investigate the oxidation state of Ni and its subsequent changes during the MOR process, we conducted mapping of the Ni 2p core-level XPS for as-prepared and exhausted samples of (857.1 and 874.2 eV) species. 57,58 Additionally, two satellite peaks were observed at higher binding energies of 861.3 and 865.3 eV. 59 Figure 11a displays the deconvoluted 1s spectra of the assynthesized solid-solution catalysts.…”

Enhanced Electrochemical Performance of CuO Capsules@CDs Composites for Solid-State Hybrid Supercapacitor

“…Moreover, three peaks at 939.2, 943.2, and 962.1 eV along with the valence states of Cu and the shake-up satellite peaks signify some distinct features of CuO. 26,27 The high-resolution peaks of O-1s at 531.5, 532.8, and 534.1 eV, corresponding to O 2− , OH, and O 2 /H 2 O, respectively, are depicted in Figure 5c. In the N-1s spectrum, three deconvoluted peaks at 397.6, 398.2, and 399.9 eV could be designated to pyridinic N, pyrrolic N, and graphitic N, respectively, in CDs of the CuO@CD nanocomposite (Figure 5d).…”

Choice of Binder on Conversion Type CuO Nanoparticles toward Building High Energy Li‐Ion Capacitors: An Approach Beyond Intercalation

“…The peak around 529.51 eV corresponds to O 2− ion in CuO, 531.37 eV links to oxygen vacancies in CuO lattice, and the peak at higher binding energy clearly indicates the hydroxyl group. [ 32 ] The C 1s peak at 284 eV in the raw spectrum represents the C–C bond due to atmospheric contamination upon loading of the sample.…”