Graphitic Carbon Coated CuO Hollow Nanospheres with Penetrated Mesochannels for High-Performance Asymmetric Supercapacitors

Abstract

We have developed a simple solvothermal–calcination strategy to synthesize continuous graphitic carbon coated hollow CuO (H–CuO@GC) spheres with excellent electrochemical performance. The H–CuO@GC spheres exhibit a high specific surface area (106.6 m2 g–1), penetrated mesochannels (∼5–15 nm), a large pore volume (0.313 cm3 g–1), a robust hollow structure, and an integral graphitic carbon layer. The H–CuO@GC sphere electrode presents high capacitance, good rate capability, and outstanding cycling ability in supercapacitors. In addition, the asymmetric supercapacitor (ASC) assembled by this structure exhibits a good rate capability (retain 75.7% at 10 A g–1) and an excellent cycling stability (90.2% capacitance retention after 10000 cycles), as well as a high energy density (38.6 W h kg–1 at a power density of 1.018 kW kg–1). This work represents a novel design strategy for the improvement of low-conductive nanomaterials applied in many fields, especially in energy applications.

Microwave-Assisted Solvothermal Synthesis of Cupric Oxide Nanostructures for High-Performance Supercapacitor

“…These properties imply the importance of supercapacitors in cameras, electric vehicles, power back-up systems, pacemakers, and airbags. , On the basis of general charge storage mechanism, supercapacitors are classified as (i) electrical double layer capacitor (EDLC) where the charge storage occurs due to non-Faradaic capacitance arising from the charge separation in a Helmholtz double layer at the electrode/electrolyte interface and (ii) pseudocapacitor, which involves Faradaic electrostatic charge storage process with redox reaction to store the charges. The latter has gained great interest because of the higher specific capacitance than EDLCs. , Moreover, all Faradaic process may not contribute to capacitive current, and those noncapacitive energy-storage processes are called supercapattery as they show noncapacitive or battery-like charge–discharge characteristics. , Transition metal oxides are the most promising active electrode materials for the pseudocapacitors or supercapattery, as several of them have multivalent oxidation states for the active redox charge transfer. , Ruthenium oxide (RuO 2 ) and hydroxide have been extensively studied due to their high theoretical specific capacitance, wide potential window, and reversible redox reactions . However, high cost, toxic nature, and need of strong acidic electrolyte limit the large scale utilization of RuO 2 -based supercapacitor .…”

Enhanced electrochemical performance of CuCo2S4/carbon nanotubes composite as electrode material for supercapacitors

“…Fig. 5a shows the CV curves of CuCo2S4, CuCo2S4/CNTs-1.3%, 3.2%, 5.0% and Co3O4/CuO/CNTs-3.2% at a scan rate of 10 mV s -1 in the potential range of 0~0.6 V. It can be seen that all the CV curves show closed patterns and have a pair of redox peaks, indicating that the energy storage mechanism of these electrodes is based on the Faradaic redox reaction processes as shown in the following equations [43][44][45][46]:…”

Research Progress on Porous Carbon Supported Metal/Metal Oxide Nanomaterials for Supercapacitor Electrode Applications

“…As a result, combined with other high-conductivity materials, cupric oxide (CuO) is beneficial to enhance electrical conductivity, and therefore, it acts as an effective material to influence the electrode properties. Zhang and his team members 194 successfully demonstrated the synthesis of graphitic carbon-coated mesoporous CuO hollow spheres (H-CuO@GC) using simple solvothermal and subsequent postcalcination methods (Figure 22a), yielding a high SSA, pore size, pore volume of 106.6 m 2 g −1 , ∼5−15 nm, and 0.313 cm 3 g −1 , respectively. Additionally, a solid, hollow structure with penetrated mesochannels and an essential graphic carbon layer is beneficial for enhancing the electrical conductivity of active materials.…”