Asymmetric supercapacitor based on vanadium disulfide nanosheets as a cathode and carbonized iron cations adsorbed onto polyaniline as an anode

Abstract

Highlights• VS 2 nanosheets electrode material was synthesized by the hydrothermal method.• C-Fe/PANI was synthesized on nickel foam by pyrolysis of the iron-PANI mixture.• The device was fabricated using VS 2 as a cathode and C-Fe/PANI as an anode.• VS 2 //C-Fe/PANI asymmetric device exhibited good electrochemical performance.ABSTRACT VS 2 nanosheets electrode material was successfully synthesized by the hydrothermal method, and the electrode material (C-Fe/PANI) based on the carbonization of Fe cations adsorbed onto polyaniline (PANI) was directly synthesized on a nickel foam (current collector) by pyrolysis of the iron-PANI mixture coated on nickel foam in a tube furnace under the N 2 atmosphere. The structural and morphological characterization of the as-synthesized electrode materials was carried out using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The electrochemical behavior of each working electrode was analyzed in a three-electrode cell configuration using 6 M KOH electrolyte, and thereafter, a hybrid (asymmetric) device was successfully fabricated using VS 2 nanosheets as the positive electrode and C-Fe/PANI as a negative electrode. The fabricated VS 2 //C-Fe/PANI asymmetric device was found to perform at a high applied potential difference of 1.7 V in 6 M KOH. At a current density of 2 A g -1 , this device exhibited high energy and power densities of 27.8 Wh kg -1 and 2991.5 W kg -1 respectively. In addition, a VS 2 //C-Fe/PANI 2 device showed excellent cycling stability with 95% capacity retention over 10 000 galvanostatic charge-discharge cycles at a current density of 5 A g -1 . storage 1. INTRODUCTION Supercapacitors (SCs) which are also referred to as electrochemical capacitors (ECs) have attracted great interest for the important application in the area of electrochemical energy storage because of increasing demand for digital communication, electric vehicles and other electric devices at high pulse power level [1-7]. Since, SCs are high power-delivery storage devices which are able to discharge in a shorter time by exploiting their fast surface or near surface reactions and delivering high power compared to conventional batteries [2,8-10]. Though, SCs are high power-delivery storage devices (have high power density) they have low energy density especially compared to rechargeable batteries (Li-ion batteries) [2,11]. Accordingly, researchfocus in SCs is on improving their energy density (i.e. ~5˗8 Wh kg -1 ) without compromising their high power density (i.e. ~5˗30 kW kg -1 ), unlike in rechargeable batteries which already have high energy density in the range of 120˗200 Wh kg -1 , the focus will be on improving the power density which is in the range of 0.4˗3 kW kg -1 [2,8,9,12]. Recently, asymmetric (hybrid) systems have been explored to increase the operating electrode potential to improve the energy density of the SCs. Generally, the behavior of the SCs is mainly influenced by the charge storage mecha...

Symmetric, Asymmetric, and Battery‐Type Supercapacitors Using Two‐Dimensional Nanomaterials and Composites

“…Many literature reports can be found which demonstrate the fabrication of asymmetric supercapacitors by using either two different TMDs or a TMD with another material (popularly carbon-based). [47,48] Though different TMDs like MoS 2 , VS 2 , WS 2 , and MoSe 2 have been frequently used to fabricate an asymmetric device, MoS 2 remains the most researched material for energy storage. [49] In 2016 Yang et al [48] demonstrated an asymmetric supercapacitor with MnO 2 and MoS 2 flower-like growth on Graphene Nanosheets (GNS) as the positive and negative electrodes, respectively.…”

Recent Developments on Emerging Properties, Growth Approaches, and Advanced Applications of Metallic 2D Layered Vanadium Dichalcogenides

“…[ 58 ] Energy density of 117 Wh kg −1 at 20.65 kW kg −1 for the vanadium sulfide‐graphene hybrids is reported whereas the value was 19 Wh kg −1 at 6 W kg −1 for bare VS 2 nanosheets. Supercapacitive performance of an asymmetric device with VS 2 nanosheets as the positive electrode and C–Fe/PANI as a negative electrode was characterized further by Rantho et al [ 117 ] The asymmetric VS 2 //C–Fe/PANI device found to be perform at a high potential up to 1.7 V in 6 m KOH with energy density of 27 Wh kg −1 at 2991.5 W kg −1 and 95% capacity retention after 10 000 cycles. VS 2 nanosheet‐based microsupercapacitors is reported to show a high specific capacitance of 4760 mF cm −2 with negligible deterioration of capacitance after 1000 cycles.…”

Current Research of Graphene-Based Nanocomposites and Their Application for Supercapacitors

“…Additional hybrid CPs with metal/metal oxides as pseudocapacitive materials for SCs are also very promising. Rantho et al successfully synthesized an asymmetric SC using VS 2 nanosheets as a cathode and carbonized iron cations adsorbed on polyaniline (C-Fe/PANI) as an anode [ 152 ]. Using 6 M KOH as an electrolyte, they evaluated the electrochemical behavior of the working electrode in a three-electrode system.…”

“…However, the results revealed that the composites had a better current response in 6 M KOH electrolyte, and the relevant explanation for such an observation was also suggested by Rantho et al They reported the specific capacitance of 516.5 F/g for VS 2 and 486.5 F/g for C-Fe/PANI. To further explore the electrochemical performance of VS 2 and C-Fe/PANI electrodes, an asymmetric device was constructed by Rantho et al The VS 2 /C-Fe/PANI asymmetric device offered a high-energy-density of 27.8 Wh/kg and a power density of 2991.5 W/kg at a current density of 2 A/g, as discussed in details elsewhere [ 152 ].…”

“… Schematic of the synthesis procedure for ( a ) VS 2 nanosheets and ( b ) C-Fe/PANI as SC electrode materials (reproduced with permission from ref. [ 152 ]). …”