In situ MoS₂ Decoration of Laser-Induced Graphene as Flexible Supercapacitor Electrodes

Abstract

Herein, we are reporting a rapid one-pot synthesis of MoS2-decorated laser-induced graphene (MoS2-LIG) by direct writing of polyimide foils. By covering the polymer surface with a layer of MoS2 dispersion before processing, it is possible to obtain an in situ decoration of a porous graphene network during laser writing. The resulting material is a three-dimensional arrangement of agglomerated and wrinkled graphene flakes decorated by MoS2 nanosheets with good electrical properties and high surface area, suitable to be employed as electrodes for supercapacitors, enabling both electric double-layer and pseudo-capacitance behaviors. A deep investigation of the material properties has been performed to understand the chemical and physical characteristics of the hybrid MoS2-graphene-like material. Symmetric supercapacitors have been assembled in planar configuration exploiting the polymeric electrolyte; the resulting performances of the here-proposed material allow the prediction of the enormous potentialities of these flexible energy-storage devices for industrial-scale production.

Simple Synthesis of Molybdenum Disulfide/Reduced Graphene Oxide Composite Hollow Microspheres as Supercapacitor Electrode Material

“…Compared with the C 1s spectrum of GO sheets, the relative intensities of peaks for the oxygen-containing groups in the C 1s spectrum of MoS 2 /RGO hollow microspheres diminish dramatically, implying that the GO sheets coated on substrate microspheres underwent an abundant removal of oxygen-containing functional groups and werethus reduced to RGO component during the hydrothermal reactions [20,33]. XPS, Mo 3d, and S 2p spectra reveal representative curves for their doublets with the binding energies (BE) of 229.5 eV for Mo 3d 5/2 , 232.7 eV for Mo 3d 3/2 , 162.3 eV for S 2p 3/2 , and 163.5 eV for S 2p 1/2 , respectively, which agree well with the values for other MoS 2 -based composites reported previously [3,25,34]. The signal of S 2s centered at 226.7 eV is also found in the Mo 3d spectrum, and the BE splitting of 3.2 eV for Mo 3d doublets as well as the BE splitting 1.2 eV for S 2p doublets manifest that the chemical states of elements Mo and S within MoS 2 /RGO hollow microspheres are +4 and −2 valence, respectively [3,25,34].…”

“…XPS, Mo 3d, and S 2p spectra reveal representative curves for their doublets with the binding energies (BE) of 229.5 eV for Mo 3d 5/2 , 232.7 eV for Mo 3d 3/2 , 162.3 eV for S 2p 3/2 , and 163.5 eV for S 2p 1/2 , respectively, which agree well with the values for other MoS 2 -based composites reported previously [3,25,34]. The signal of S 2s centered at 226.7 eV is also found in the Mo 3d spectrum, and the BE splitting of 3.2 eV for Mo 3d doublets as well as the BE splitting 1.2 eV for S 2p doublets manifest that the chemical states of elements Mo and S within MoS 2 /RGO hollow microspheres are +4 and −2 valence, respectively [3,25,34]. Namely, they exist in the form of Mo 4+ and S 2− , which should come from S–Mo–S bonds [25,34].…”

“…The signal of S 2s centered at 226.7 eV is also found in the Mo 3d spectrum, and the BE splitting of 3.2 eV for Mo 3d doublets as well as the BE splitting 1.2 eV for S 2p doublets manifest that the chemical states of elements Mo and S within MoS 2 /RGO hollow microspheres are +4 and −2 valence, respectively [3,25,34]. Namely, they exist in the form of Mo 4+ and S 2− , which should come from S–Mo–S bonds [25,34]. …”

“…Specifically, its extraordinary electric conductivity and long-term chemical stability make it widely applicable in the fields of energy storage and conversion, and hence lots of graphene or reduced graphene oxide (RGO)-containing composites with reinforced electrochemical behaviors have been explored [5,17,22]. Typically, MoS 2 /graphene and MoS 2 /RGO hybrid materials were fabricated by different methods and the corresponding electrodes gave pronounced supercapacitive performances [23,24,25]. For instance, layered MoS 2 was directly deposited on RGO sheets by microwave-assisted synthesis approach, MoS 2 nanosheet−graphenenanosheet hybrid films were developed via layer-by-layer techniques, and in situ decoration of laser-induced graphene with MoS 2 was accomplished by spin-coating MoS 2 nanoflakes onto polyimide foil followed by graphenization of the polymer using a CO 2 laser-writing process.…”

The Effects of Morphology Re-Arrangements on the Pseudocapacitive Properties of Mesoporous Molybdenum Disulfide (MoS2) Nanoflakes

“…14 In the last three years, it is interesting to observe that MoS 2 has begun to attract interest even as full cell (2-electrode) configurations. 12,[15][16][17][18][19][20] The supercapacitor performance of MoS 2 has been compared to that of the carbon nanotubes (CNT) array electrodes. 6,21 Spherical morphology of the MoS 2 remains the most investigated morphology for supercapacitor application.…”