Substrate-integrated core–shell Co₃O₄@Au@CuO hybrid nanowires as efficient cathode materials for high-performance asymmetric supercapacitors with excellent cycle life

Abstract

Designing Co3O4@Au@CuO core–shell nanowire cathode for a high-performance α-Fe2O3//Co3O4@Au@CuO hybrid asymmetric supercapacitors (ASCs).

Designing Core‐Shell Ni(OH)2@CuO Nanowire Arrays on 3D Copper Foams for High‐Performance Asymmetric Supercapacitors

“…In the Ni 2p spectrum (Figure b), there is a pair of obvious spin orbit doublets at 873.7 and 856.1 eV, representing the Ni 2p 3/2 and Ni 2p 1/2 oxidation states (Ni 2+ ), with spin energy separation of 17.6 eV, which evidence the formation of Ni(OH) 2 . The other two speaks at 879.4 eV and 861.4 eV are broad satellites labeled with “sat.” Figure c depicts that the deconvoluted Cu 2p peaks at 953.7 eV and 933.8 eV correspond to Cu 2p 3/2 and Cu 2p 1/2 oxidation states (Cu 2+ ), which proves the surface of copper foam has been completely oxidized to CuO . Meanwhile, four small satellite peaks at 962.4, 943.7, 941.4, and 934.5 eV illustrate the CuO existence in the composite .…”

“…[21] Figure 4c depicts that the deconvoluted Cu 2p peaks at 953.7 eV and 933.8 eV correspond to Cu 2p 3/2 and Cu 2p 1/2 oxidation states (Cu 2 + ), which proves the surface of copper foam has been completely oxidized to CuO. [19] Meanwhile, four small satellite peaks at 962.4, 943.7, 941.4, and 934.5 eV illustrate the CuO existence in the composite. [15] In addition, the spectrum of O1s (Figure 4d) exists four peaks located at 532.1, 531.1, 530.4, and 529.7 eV, in which two peaks (532.1 and 531.1 eV) represent the hydroxyl-metal bonds in Ni(OH) 2 , others (530.4 and 529.7 eV) correspond to and oxy metal bonds in CuO.…”

“…For three‐electrode configurations, The specific capacitance (C) can be calculated by the following equation [Eq. ]: …”

“…[18] (4) Building up the Ni(OH) 2 (high specific capacity but poor cycling stability) and CuO (good cycling stability but low specific capacity) active materials to construct the electrodes with good comprehensive performance. [19] Also, both the core and shell materials were good pseudocapacitive materials. Hence, the hierarchical Ni(OH) 2 @CuO electrode delivers outstanding specific capacity of 1.625 F cm À 2 at 3 mA cm À 2 (equivalent to 1451 F g À 1 at 0.54 A g À 1 ).…”

“…(3) The core‐shell structure of Ni(OH) 2 @CuO promotes the intimate electrode/electrolyte contact and can avoid the aggregation of Ni(OH) 2 , protect the substrate from corrosion as well . (4) Building up the Ni(OH) 2 (high specific capacity but poor cycling stability) and CuO (good cycling stability but low specific capacity) active materials to construct the electrodes with good comprehensive performance . Also, both the core and shell materials were good pseudocapacitive materials.…”