The development of low cost supercapacitor cells with unique capacitive properties is essential for many domestic and industrial purposes. Here we report the first ever application of SnS-reduced graphene oxide (SnS/RGO) layered nanocomposite as a superior electrode material for symmetric aqueous hybrid supercapacitors. We synthesized SnS/RGO nanocomposite comprised of nanosheets of SnS and graphene oxide via a one-pot hydrothermal approach. in situ as-synthesized SnS/RGO is devised for the first time to give high specific capacitance 500 Fg, energy density 16.67 Wh kg and power density 488 W kg. The cell retains 95% charge/discharge cycle stability up to 1000 cycles. In-short, the SnS/RGO nanosheet composite presented is a novel and advanced material for application in high stability moderate value hybrid supercapacitors. All the currently available surveys in literature state the potential applicability of SnS as the anode material for reversible lithium/sodium ion batteries (LIBs/NIBs) but there is a lack of equivalent studies on electrochemical capacitors. We filled up this knowledge gap by the use of the same material in a cost-effective, highly active hybrid supercapacitor application by utilizing its pseudocapacitance property combined with the layered capacitance property of graphene sheets.
A new strategy for the synthesis of fluorescent monodispersed 2-dimensional (2D) CdSe/CdS core/shell hexagonal platelet nanocrystals has been demonstrated. Because of the stronger affinity of the -NH2 group of oleylamine to the (0001Se) facet comprising three dangling bonds in CdSe seeds, oleylamine acts as the sole surfactant responsible for hindering the growth of the CdS shell in the 0001 and 0001[combining macron] facets and for helping the shell growth anisotropically in the 〈100〉 direction. The as-synthesized products were thoroughly characterized using XRD, TEM/HRTEM, HAADF and STEM for determining the crystal structure, growth mechanism and the position of the seed inside a core/shell nanocrystal. Optical absorption, PL, PLE and TRPL studies revealed efficient photoexcitation and the possibility of polarized emission from 2D core/shell nanocrystals.
Although nanostructured NiCo 2 O 4 is the most appealing and studied electrode material by far as it is cheap, nontoxic, and efficient for supercapacitor application, it still lacks suitable device application comprising a wide voltage window and high operating current density, high specific energy and power, and absolute stability. Here, we report a successful application of our NiCo 2 O 4 nanoparticles (NPs) in a highly efficient electrochemical supercapacitor device, which is brought to reality because of the NPs' fast ion intercalation/extraction and fast reversible Faradaic surface reactions. The as-synthesized spinel NiCo 2 O 4 NPs are 65 nm in average diameter, have 59 m 2 /g of surface area, and 0.44 cm 3 /g of pore volume. Charge storage capability and reliability of the material as an active electrode have been demonstrated in terms of a conventional three-electrode method and in a coin-cell device. Specific capacity values of 150.56 to 41.66 mAh•g −1 (1084 to 300 Fg −1 in terms of capacitance) have been realized in the applied potential window (0.0−0.5 and 0.0−1.5 V) and in current densities of 2 to 10 Ag −1 , which are >98% stable in any of these given conditions up to 20 000 measured charge−discharge cycles. The NiCo 2 O 4 NP electrode exhibits a maximum energy density of 10.42 Wh kg −1 and a power density of 3750 Wkg −1 at 10 Ag −1 and makes itself an efficient electrode material for superior supercapacitor devices. These high performances are corroborated to the ultrafast intercalation reaction of electrolyte ions with nickel cobaltate at the electrode surface.
Multicomponent hybrid nanocrystals (HNC) consisting of a semiconductor and metallic domains are an important class of nanostructured materials demonstrating useful applications and interesting basic knowledge. In this scenario, Au nanoparticle (NP) islands of ∼2 nm have been grown on unique two dimensional (2D) CdSe/CdS core@shell hexagonal nanoheteroplatelets of 20 nm diameter to form unprecedented 2D CdSe/CdS-Au HNCs and detailed optical characterization has been carried out to determine the dimensionality based electron transfer dynamics on the ultrafast scale. Steady state optical absorption studies show that upon growing Au NPs onto the 2D nanoplates, a new band appears in the red region of the spectra (500-800 nm), which suggests a strong interaction between the exciton of the core-shell and the plasmon of the metal NPs. Fluorescence studies showed the quenching of emission of the semiconductor domains upon the growth of the metallic domains. Detailed optical and TRPL studies suggested efficient charge transfer from the 2D CdSe/CdS to the Au domains, irrespective of excitation wavelength. Femtosecond transient absorption studies suggest that the electron transfer from the 2D hybrid nanocrystals to the metal domain is on an ultrafast time scale (∼800 fs). No evidence is observed for charge transfer from the 2 nm Au domains to the semiconductor seeds. The broad absorption in the visible region of the hybrid nanocrystals and the ultrafast charge transfer facilitates very efficient photo-catalytic reactions under direct sun light, as a case study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.