In situ Growth of Cu2O/CuO Nanosheets on Cu Coating Carbon Cloths as a Binder-Free Electrode for Asymmetric Supercapacitors.

Lina Xu,Xue Guo,Hua Zhang,Haibin Sun,Xiaojiao Zhang,Jiao Li,Jiakun Xu

doi:10.3389/fchem.2019.00420

Abstract

Cu2O/CuO nanosheets in-situ grown on Cu-Carbon cloths (Cu-CCs), namely Cu2O/CuO@Cu-CCs, are constructed by a simple strategy with electroless copper plating, chemical etching, and thermal dehydration. The as-prepared material is directly used as binder-free electrodes for supercapacitors (SCs). CCs coated with Cu, as the current collector, can effectively promote the charge collection and electron transfer, while the hierarchical Cu2O/CuO nanosheets provide massive active sites for fast faradic reactions. The composite electrode exhibits high specific capacitance [1.71 F cm−2, equivalent to 835.2 F g−1, at the current density of 10 mA cm−2 (3.57 A g−1)]. The asymmetric supercapacitor device using Cu2O/CuO@Cu-CCs as the positive electrode and activated carbon as the negative electrode, achieves a superior energy density up to 60.26 Wh kg−1 at a power density of 299.73 W kg−1 and an excellent long-term cycling stability (9.65% loss of its initial capacitance after 5,000 cycles). The excellent electrochemical performance is mainly ascribed to the unique hierarchical structure of Cu2O/CuO@Cu-CCs, making it attractive as a potential electrode material for high performance SCs.

Highlights

Supercapacitors (SCs), one of the most promising energy storage devices, have received extensive attention owning to their high power density, fast charge/discharge speed, long cycling life span, and low-cost (Lu et al, 2014; Xiong et al, 2015; Sami et al, 2017; Dai et al, 2018)
For PCs, the energy is stored within the electrode through the faradic redox reaction while taking transition metal oxides/hydroxides and conducting polymers as the electrode materials, the PCs provide much higher energy density and specific capacitance than electrical double layer capacitors (EDLCs)
The asymmetric supercapacitor (ASC) device was assembled by using Cu2O/CuO@Cu-Carbon cloths (Cu-carbon cloths (CCs)) electrode and active carbon electrode as the positive and negative electrode, respectively

Summary

Introduction

Supercapacitors (SCs), one of the most promising energy storage devices, have received extensive attention owning to their high power density, fast charge/discharge speed, long cycling life span, and low-cost (Lu et al, 2014; Xiong et al, 2015; Sami et al, 2017; Dai et al, 2018). Cu2O/CuO nanosheets in situ grown on CCs provide sufficient active sites for charge/discharge electronic, which is important for energy storage of supercapacitor.

Results

Conclusion