The development of cost-effective and scalable synthetic methods is of paramount importance to achieve industrial application of energy conversion and storage devices based on layered double hydroxides (LDH). Herein, we synthesized NiCo-LDH nanosheets via a simple up-scalable coprecipitation method at relatively low temperature. Moreover, we used several characterization techniques to unveil the unique properties of the novel NiCo-LDH among which XRD, EDS, XPS and FT-IR. Consequently, we further investigated NiCo-LDH nanosheets using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to evaluate the electroactivity of the as-synthesized NiCo-LDH for energy storage. Overall, the electrochemical test of the as-synthesized NiCo-LDH revealed remarkable performance exhibiting a specific capacitance as high as 2,140 Fg-1 (5 mV/s).

No abstract

The washing of layered double hydroxides (LDH) material is mostly purposed to discard the unreacted products after the reaction has been completed. However, this study demonstrated that the washing stage can also be targeted to optimise the electrochemical performance of LDH by using an appropriate solvent. Solvents, namely, ethanol, acetone, and an ethanol–acetone solution (2:1) were used for the washing of LDH and the impacts thereof on the structural, physical, chemical, morphological, and electrochemical properties were investigated. Using Williamson–Hall analysis, we observed modifications on the crystalline domain. The specific surface area and pore parameters for all the samples were also differently affected. The Fourier transform infrared (FTIR) measurements displayed evident changes in the basic sites. The electrochemical performances of samples were analysed. The sample washed with the ethanol–acetone solution exhibited a specific capacitance of 1807.26 Fg−1 at 10 mVs−1, which is higher than that of other samples as well as low internal resistance compared to its counterpart. This demonstrates that the use of an appropriate solvent during the washing stage of LDH affects the electrochemical properties.

A facile hydrothermal technique was employed to synthesized non-modulated cobalt-doped molybdenum sulfide (MoS 2 ) nanoflowers. The as-prepared materials were coated on commercially available Ni-foam to fabricate electrode materials for supercapacitor applications. The elucidation of the structural information, surface morphology, microstructural properties, as well as surface areas was successfully carried out by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) measurements, respectively. XRD and Raman analysis confirmed the structural changes of the materials, which depict a successful synthesis of cobalt-doped MoS 2 with typical phase change and the redshifted peaks of Raman spectra compared to pristine MoS 2 . The flower-like morphology and agglomerating nanosheets of various nanometer diameters of the microstructural properties of the obtained Co-MoS 2 were established from SEM and TEM images. The surface areas of the CMS 1 and CMS 3 electrode materials were, respectively, calculated to be 18.0607 and 14.5519 mg À2 from BET surface analysis. The electrode materials were electrochemically evaluated for their energy storage performance, the materials exhibit specific capacitances of 164 and 146 Fg À1 at 1 Ag À1 for the working electrodes (CMS 1 and CMS 3 ), respectively. Also, the energy densities of 3.67 and 2.05 Wh/kg with power densities of 3279.97 and 2960.26 W/kg were calculated for both electrode materials, respectively. The results illustrate that the Co-MoS 2 can be suitable for an effective electrode material for prospective supercapacitor applications. NOVELTY STATEMENT• Non-modulated Co-MoS 2 was synthesized via facile hydrothermal techniques.• It was established that any concentration of Cobalt higher than 3 moles might reduce the performance of the nanocomposite.