Construction of leaf-like CuO–Cu₂O nanocomposites on copper foam for high-performance supercapacitors

Abstract

Leaf-like CuO-CuO nanosheets have been prepared on copper foam by a one-step simple anodization method, which can be used as an advanced binder-free supercapacitor electrode. The performance of the CuO-CuO/Cu foam electrode was optimized through controlling and restraining the current density and reaction time. The prepared electrode exhibits a very high specific capacitance (1.954 F cm at a scan rate of 2 mV s), excellent durability (120% retention after 5000 cycles), remarkable rate capability (91.8% retention upon increasing the current density by 10 times) and good coulombic efficiency (78.2% at a current density of 2 mA cm). The facile and cost-effective fabrication process is also suitable for large scale practical production. These results indicate the leaf-like CuO-CuO/Cu foam electrode would be a promising electrode for high-performance supercapacitor applications.

In Situ Construction of Ag/Ni(OH)2 Composite Electrode by Combining Electroless Deposition Technology with Electrodeposition

“…The good cyclic properties are beneficial from the effective bonding between the active material and copper foam. Furthermore, as seen from the inset of Figure 5d, the average equivalent series resistance (R ESR ) is 0.952 Ω cm −2 based on the equation in the Supplementary Materials [30]. The low R ESR is attributed to the direct growth of AgNCs on copper foam substrate, which ensures a close bonding between them.…”

“…Corresponding to current density of 2, 4, 8, 12, 16, 20 mA cm −2 , the specific capacitances are about 3.692, 3.258, 2.632, 2.376, 2.186 and 2.024 F cm −2 , respectively (Figure 5c). The areal capacitance of Ag/Ni(OH) 2 electrode are derived from the equation in Supplementary Materials [29,30]. When the current density is 2 mA cm −2 , the coulombic efficiency reaches 88.3%, which illustrates the great redox reversibility of the pseudocapacitive material.…”

Hierarchical Core/Shell Structured Ag@Ni(OH)2 Nanospheres as Binder-Free Electrodes for High Performance Supercapacitors

“…The specific capacitance of Ag@Ni(OH) 2 decreases from 1.864 to 0.760 F cm −2 , corresponding to the discharge current density from 2 to 20 mA cm −2 , respectively, which are much higher than Ni(OH) 2 and Ag electrodes. Meanwhile, the average equivalent series resistance (R ESR ) is 0.988 Ω cm −2 , the equation and data (Table S2) are displayed in Supplementary Materials [8] (Figure 6d). The low R ESR is attributed to the direct growth of Ag on copper foam substrate using galvanic replacement reaction that leads to strong interaction between them.…”

“…But the relatively low conductivity and active surface areas often limit the effective utilization of electrode materials, and lead to the reduction of energy and power density. To address these problems, three strategies have been conceived: (1) Constructing hybrid materials by adding components or elements with high conductivity, such as graphene, Ag, Au and Cu; (2) Designing various hierarchical structures, forming porous structure or reducing particle size in order to increase the specific surface area of the active materials; (3) Adopting chemically stable conductive substrates with proper surface modification, such as copper foam [8], stainless steel mesh [9], cotton textile [10] and paper [11]. For example, Gong and coworkers [12] fabricated Ni(OH) 2 -Cu hybrid electrode by hydrothermal method, which exhibited an ultrahigh areal capacitance of 8.66 F cm −2 at 1 mA cm −2 .…”

Electrochemically anodized one-dimensional semiconductors: a fruitful platform for solar energy conversion

“…Cu , Cu 2OH CuO H O. 5 2 2 In another typical work, He and co-workers [111] demonstrated the fabrication of leaf-like CuO-Cu 2 O nanostructure on the copper foam by anodization and it exhibits 3D connect and quasi-connect structure, which provides abundant redox active sites, shortens ion diffusion pathway and improves the electrolyte penetrating efficiency. Another merit of anodization in fabricating Cu-based nanostructures is that heterogeneous oxide growth on the same substrate can be efficiently achieved by changing the appropriate oxidation conditions rather than introducing other reagents, which is difficult to achieve by other methods.…”