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Summer Research Fellowship Programme of India's Science Academies

Nanostructured Ternary Chalcogenide Electrode Materials for Electrochemical Energy Storage

Jomiya Chacko

University Of Kerala, St. Michael's College, Chertala, 688539

Dr. R B Rakhi

Photonics and Photosciences, Chemical Science and Technology Division, CSIR-NIIST, Trivandrum, 695019

Abstract

From portable electronics and transportation systems to backup systems that complement renewable sources such as solar and wind, the demand for energy storage is expected to grow substantially well into the foreseeable future. Electrochemical capacitors (ECs) or supercapacitors are energy-storage devices which possess higher energy density (0.5–10 Wh/kg) than conventional dielectric capacitors and higher power density (1–10 kW/kg) than batteries. ECs find applications in electric vehicles, uninterruptible power supplies, DC power systems, and mobile devices. A supercapacitor stores energy using either ion adsorption (electrical double layer capacitors, EDLCs) or fast and reversible Faradic reactions (pseudocapacitors). These two mechanisms can function simultaneously, depending on the nature of the electrode material. While EDLCs, the most common supercapacitors at present, use carbon-based active materials with high surface area as the electrode materials, pseudocapacitors use transition metal oxides or transition metal sulfides or electrically conducting polymers as active materials. Because of the highly versatile electronic structure and high surface area, the transition metal sulfide, Molybdenum disulfide (MoS2) can be considered as an excellent electrode material for electrochemical energy storage applications. The capacitive performance of MoS2 can be further improved by the doping of the material with either Fe2+ or Co3+ or Ni3+ ions.

With the existence of additional redox sites and tunability over the interlayer distance by suitable substitution, the ternary chalcogenides have great potential as electrode materials for supercapacitors. In this work, a ternary chalcogenide, CoMoS2, has been synthesized by a hydrothermal route and has been used as the active electrode material for supercapacitor. In the present study, the as-prepared CoMoS2 nanosheets have been characterized by powder X-ray diffraction, TEM, SEM, BET, FTIR, and Raman analysis. The electrochemical properties of the CoMoS2 nanosheets have been analyzed by cyclic voltammetry (CV), galvanostatic charge-discharge (CD), and electrochemical impedance spectroscopy measurements in symmetric configuration and the results are discussed.

Keywords or phrases: Supercpacitor, Hydrothermal, CoMoS2

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