Hybrid Reduced Graphene Oxide/Manganese Diselenide Cubes: A New Electrode Material for Supercapacitors

Abstract

The integration of 2 D graphene nanosheets and layered transition‐metal dichalcogenides has been recognized as one of the most extensive strategies for the synthesis of promising electrode materials for energy‐storage devices. In this study, cubic manganese diselenide (MnSe2) and hybrid reduced graphene oxide/MnSe2 (G‐MnSe2) materials were synthesized by a facile hydrothermal method. Metallic selenium impurities are considered to be a major unwanted byproduct in this method. An effective means to remove such bulk chalcogenides is a key challenge. For the synthesis of the G‐MnSe2 hybrid material, we used a strategy in which the graphene oxide was mixed with manganese and selenium precursors. Surprisingly, the final G‐MnSe2 product contained a negligible amount of selenium impurity. The MnSe2 and G‐MnSe2 hybrid materials were characterized in detail. For the first time, the electrochemical energy‐storage behavior of MnSe2‐based materials was assessed for supercapacitor applications. The specific capacitance of the MnSe2 electrode was approximately 57.8 mF cm−2, whereas the hybrid G‐MnSe2 electrode showed a much higher specific capacitance of 93.3 mF cm−2 at a scan rate of 1 mV s−1. A symmetric cell made from the G‐MnSe2 hybrid material showed excellent long‐term stability for 4500 cycles and approximately 106 % retention of its initial capacitance, which is impressive compared with the cycle life of the MnSe2‐based symmetric cell (80 % capacitance retention at the 4500th cycle).

Large energy storage efficiency of the dielectric layer of graphene nanocapacitors

“…In practical applications, the measured property is usually not the residual polarization or the residual charge, but the discharge current. Generally, for times much longer than the RC relaxation time of the capacitor, the discharge current due to different mechanisms of charge retention by dielectric can be described by the fractional power law ~ t -α , with different mechanisms resulting in different values of the power α [6]. The varying time dependence of the discharge currents resulting from different mechanisms of charge absorption can in principle be used to eliminate some mechanisms for a particular dielectric, or to analyze the relative contributions of those mechanisms.…”

“…Graphene is a smooth material so the field enhancement factor should be low. Graphene has been used previously for making capacitors and other nanoscale devices [6,7,8,9,10]. Nanocapacitors based on graphene or similar metallic nanomaterials capping very thin dielectrics in between have been a subject of active study.…”

A Blended SPS-ESPS Control DAB-IBDC Converter for a Standalone Solar Power System

“…where k = Voltage transfer ratio. From the Equations (6) and (15), it is noted that the back-flow power (P bf ) is directly proportional to the voltage transfer ratio 'k', so the back-flow power for this DAB-IBDC design also will be the maximum as it has the maximum k value. Therefore, to increase the power conversion efficiency in such a large input to output voltage variation, this paper proposed a combination of SPS and ESPS control algorithm.…”

Graphene‐Polymer//Graphene‐Manganese Oxide Nanocomposites‐Based Asymmetric High Energy Supercapacitor with 1.8 V Cell Voltage in Aqueous Solution

“…It is well known that conducting polymers itself widely used in supercapacitors and combination of graphene nanosheets and conductive polymer nanocomposites will significantly improve the specific capacitance . In general, the graphene and graphene‐based nanocomposite electrode materials are widely used as negative electrodes in asymmetric supercapacitors ,,…”