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A stable and high-energy hybrid supercapacitor using porous Cu2O-Cu1.8S nanowire arrays

Esfandiar, A ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1039/c9ta12675a
  3. Publisher: Royal Society of Chemistry , 2020
  4. Abstract:
  5. A three-dimensional electrode based on porous Cu2O-Cu1.8S nanowires is prepared by means of a facile fabrication process. In this electrode, nanowires are decorated with Cu1.8S polyhedral nanostructures on the top, which are directly grown on a copper foam, thereby eliminating the need for a polymer binder. As an electrochemical electrode, it exhibits an extrinsic pseudocapacitive charge storage mechanism, which is different from that of battery-like Cu2O-CuO and Cu(OH)2 electrodes. The areal and volumetric capacitances of the Cu2O-Cu1.8S electrode can reach 2.6 F cm-2 and ∼200 F cm-3, respectively, at 2 mA cm-2, which are much higher than those obtained using copper(i, ii) oxide and hydroxide phases. An asymmetric hybrid supercapacitor device shows areal and volumetric energy densities of 204.8 μW h cm-2 and ∼2.1 mW h cm-3, respectively, at a power density of 3.1 mW cm-2 with a retention ratio of 55% at 15.5 mW cm-2. Besides, both the Cu2O-Cu1.8S electrode and the asymmetric hybrid supercapacitor device exhibit remarkable long-Term cycling stabilities, with the capacitance retention of 91% and 94% after 15 000 cycles at the current densities of 40 and 20 mA cm-2, respectively. The porous copper sulfide phase in the fabricated electrode provides a reservoir of ions close to the surface, reducing the diffusion path lengths of ions into the electroactive solid network; this induces an improved electrochemical pseudocapacitive behavior. Our findings shed light on the role of surface modification for creating stable energy storage devices and present a simple way using cost-effective materials to generate more accessible active sites for charge storage on nanostructured electrodes. © 2020 The Royal Society of Chemistry
  6. Keywords:
  7. Capacitance ; Copper oxides ; Cost effectiveness ; Electrochemical electrodes ; Nanowires ; Storage (materials) ; Supercapacitor ; Capacitance retention ; Facile fabrication ; Hybrid supercapacitors ; Nano-structured electrodes ; Pseudocapacitive behavior ; Three-dimensional electrode ; Volumetric capacitance ; Volumetric energy densities ; Sulfur compounds
  8. Source: Journal of Materials Chemistry A ; Volume 8, Issue 4 , 2020 , Pages 1920-1928
  9. URL: https://pubs.rsc.org/en/content/articlelanding/2020/ta/c9ta12675a#!divAbstract