Synthesis of non-planar graphene-wrapped copper nanoparticles with iron(III) oxide decoration for high performance supercapacitors

Abstract

The performance of supercapacitors strongly depends on the electrochemical characterizations of electrode materials. Herein, a composite material consisted of iron(III) oxide (Fe2O3) and multilayer graphene-wrapped copper nanoparticles (Fe2O3/MLG-Cu NPs) is fabricated on a flexible carbon cloth (CC) substrate via two-step synthesis process for supercapacitor application. Where, MLG-Cu NPs are prepared on CC by one-step chemical vapor deposition (CVD) synthesis approach; thereafter, the Fe2O3 is further deposited on the MLG-Cu NPs/CC via successive ionic layer adsorption and reaction (SILAR) method. The related material characterizations of Fe2O3/MLG-Cu NPs are well investigated by scanning electron microscopic (SEM), high resolution transmission electron microscopy (HR–TEM), Raman spectrometer and X-ray photoelectron spectroscopy (XPS); the electrochemical behaviors of the pertinent electrodes are studied by cyclic voltammogram (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements. The flexible electrode with Fe2O3/MLG-Cu NPs composites exhibits the best specific capacitance of 1092.6 mF cm-2 at 1 A g-1, which is much higher than those of electrodes with Fe2O3 (863.7 mF cm-2), MLG-Cu NPs (257.4 mF cm-2), multilayer graphene hollow balls (MLGHBs, 14.4 mF cm-2) and Fe2O3/MLGHBs (287.2 mF cm-2). Fe2O3/MLG-Cu NPs electrode also exhibits an excellent GCD durability, and its capacitance remains 90% of its original value after 1200 cycles of the GCD process. Finally, a supercapacitor system consisted of four Fe2O3/MLG-Cu NPs/CC electrodes can efficiently power various light-emitting diodes (i.e., red, yellow, green, and blue lights), demonstrating the practical application of Fe2O3/MLG-Cu NPs/CC electrode.

Editorial for focus on manipulations of atomic and molecular layers and its applications in energy, environment sciences and optoelectronic devices

“…In addition to these ALD efforts, in this Focus, there are also 5 studies relying on wet chemistry, CVD, and other techniques. Among them, two studies studied supercapacitors [18,19]. To develop flexible Fe 2 O 3 -based supercapacitors, Cu nanoparticles (NPs) wrapped a conductive multi-layer graphene (MLG) were fabricated on top of the CC using a CVD method, while the pseudocapacitive γ-Fe 2 O 3 was fabricated using a successive ionic layer adsorption and reaction (SILAR) method at a low temperature.…”