CuCo₂O₄ Nanorods Coated with CuO Nanoneedles for Supercapacitor Applications

Abstract

Herein, we report the chemical synthesis of a core−shell nanoarchitecture comprising CuCo 2 O 4 @CuO (CCO@ CuO) on a flexible stainless steel mesh substrate (FSSM) with CuCo 2 O 4 (core) and CuO (shell) by a simple, cost-efficient, additivefree hydrothermal deposition method, followed by successive ionic layer adsorption and reaction method for fabricating a flexible electrode for an asymmetric supercapacitor (ASC). The nanocomposite of CCO@CuO revealed a high surface area of 98.33 m 2 g −1 and the electrode delivered a high specific capacitance of 713 F g −1 at a high current density of 11 mA cm −2 , which was noted to be higher than those of the individual constituent CuO (436 F g −1 ) and CuCo 2 O 4 (443 F g −1 ) metal oxide electrodes. The CCO@CuO electrode demonstrated remarkable cycling stability (∼90% capacitance retention after 5000 charge−discharge cycles at 15 mA cm −2 ). The ASC device CCO@CuO//rGO (reduced graphene oxide) delivered a maximum energy density of 37.43 Wh kg −1 at a power density of 250 W kg −1 . The device revealed 83% capacitance retention after 4000 cycles. These results indicate that the CCO@CuO/FSSM electrode is a promising functional material for energy storage devices.

In Situ Construction of Binder-Free Stable Battery-Type Copper Cobaltite and Copper Oxide Composite Electrodes for All-Solid-State Asymmetric Supercapacitors: Cation Concentration and Morphology-Dependent Electrochemical Performance

“…Hence, it is necessary to formulate an ecological energy plan to overcome major disputes over traditional energy sources. The next generation of electrical and electronic equipment requires efficient, low-cost, and safe clean energy storage systems. − In this regard, supercapacitors (SCs) have proven to be clean energy storage devices to meet current market requirements because of the high power density, moderate energy density, quick charge and discharge rates, retentive cycling, wide operating temperature, environmental protection, safety, and cost-effectiveness. − Owing to these outstanding advantages, SCs are used in household appliances, biomedical devices, and transportation sectors. , However, the SC applications are limited in the high-energy-density applications, where batteries have already been used. Advanced research work on SCs has been tending globally to increase energy density without loosening power density, cost, and safety measurements to surpass high-energy-density batteries …”

Tunable Fabrication of Hollow Nano Sword-Like CuCo2O4 Derived from Bimetal–Organic Frameworks as Binder-Free Electrodes

“…As revealed in Figure g, the device can maintain more than 90% of its original capacitance after 8000 cycles, confirming the outstanding cycling stability of our device at a high voltage without an apparent polarization. A Ragone plot comparing the energy densities and power density values of the CCO-HS//AC device with other previously reported supercapacitors is seen in Figure h. − As illustrated, the CCO-HS//AC device delivered the highest energy density and power density of 54 Wh kg –1 and 3137 W kg –1 , respectively. Finally, in order to show the real application of our device, we connected two devices in series, and after charging for less than 1 min, they could power 14 green LEDs (Figure ).…”

CuxO-Modified Nanoporous Cu Foil as a Self-Supporting Electrode for Supercapacitor and Oxygen Evolution Reaction

“…The energy densities of our device are in the range of 20.86 to 24.20 Wh kg −1 (0.26 to 0.30 Wh cm −2 ), corresponding to the power densities of 2.14 to 0.65 kW kg −1 (26.49 to 8.08 W cm −2 ). The energy densities are competitive with some other Cu x O-based supercapacitors (Table S2) [26,27,36,38,39,[43][44][45]. For instance, a 3D Cu 2 O@Cu nanoneedle arrays electrode had an energy density of 26.0 Wh kg −1 at power density of 1.8 kW kg −1 [27].…”

“…The electrode has unchanged phase compositions after cycling, and the Cu x O flakes become thicker than the initial structure (Figure S12 and inset of Figure 5i). We compared the specific capacitance of Cu x O-based electrodes, as shown in Table S1 [ [25][26][27]36,38,39,[41][42][43][44][45], and the results reveal that our electrode is comparable to the pure Cu x O material but inferior, compared to the Cu x O-based composites. Further investigations might be carried out to fabricate hybrid electrodes based on our materials.…”