Enhanced energy storage performance and theoretical studies of 3D cuboidal manganese diselenides embedded with multiwalled carbon nanotubes

The burst of energy produced from the sustainable energy sources need to be harnessed by energy storage systems. Development of novel and advanced energy storage devices such as supercapacitors discover an enormous future ahead. Recently, hybrid supercapacitors (electric double layer capacitor (EDLC) and pseudocapacitors) trend to be used as energy storage interfaces for their improved efficacy in energy density without altering the power density. In the ongoing workplan, transition metal selenides MnSe₂ and its hybrid with multiwalled carbon nanotubes (MWCNTs) are synthesized by a simplistic hydrothermal protocol. Certainly, cubic phases of MnSe₂-MWCNT(MS/CNT) manifested superior electrochemical performance in both symmetric and asymmetric full cell configurations in contrast to prestine MnSe₂(MS). The asymmetric MS/CNT cell achieved an excellent charge storage capability with an high energy density of 39.45 Wh kg^-1 at a power density of 2.25 kW kg^-1 maintaining an energy density of 14.5 Wh kg^-1 at a high power density of 4.5 kWh kg^-1 and also revealed long term stability over 5000 consecutive charge/discharge cycles (capacitance retention of 95.2%). Furthermore, the preferable growth along (200) direction in the presence of MWCNTs favoured in enriching the supercapacitive property of MS. The quantum capacitance of MnSe₂surfaces and MS/CNT heterostructure has been estimated using density functional theory simulation to confirm the experimental outcomes. Theoretical investigation simultaneously exposed the contribution of (200) plane of MnSe₂ and MWCNTs cultured in enhanced DOS (density of states) near the Fermi level that remarkably promoted the energy storage efficiency of MS/CNT.

Comparative electrochemical energy storage performance of cobalt sulfide and cobalt oxide nanosheets: experimental and theoretical insights from density functional theory simulations

We have investigated the origin of enhanced energy storage performance of Co₃S₄ as compared to Co₃O₄ both by supported experimental and density functional theory investigations.

Synthesis of CuSbS2 Nanoplates and CuSbS2-Cu3SbS4 Nanocomposite: Effect of Sulfur Source on Different Phase Formation

Layered CuSbS₂ and related ternary metal chalcogenides have attracted huge research interest due to their potential applications in sustainable energy storage, photovoltaics, and related area. Here, we report facile synthesis of CuSbS₂ nanoplates and CuSbS₂-Cu₃SbS₄ nanocomposite using hot injection method with varying sulfur precursors. Elemental sulfur (S₈) as sulfur precursor results in nanoplates of pure CuSbS₂, while thioacetamide (TA) as sulfur source gives nanocomposite with Cu₃SbS₄ nanoparticle decorated on the surface of CuSbS₂ nanoplates. The ease of reduction of TA as compared to sulfur at high temperature, in the presence of oleylamine, promotes the oxidation of antimony from (III) to (V) state and the formation of Cu₃SbS₄ phase containing Sb(V). Raman scattering study confirms the presence of Cu₃SbS₄ phase in CuSbS₂-Cu₃SbS₄ nanocomposite. X-ray photoemission spectroscopy study on CuSbS₂ nanoplates and CuSbS₂-Cu₃SbS₄ nanocomposite confirms the desired valence state of the constituent elements. Electrochemical properties measurement shows better specific capacitance for CuSbS₂-Cu₃SbS₄ nanocomposite (151 F/g) as compared to CuSbS₂ nanoplates along with long-term cyclic stability with 68.2% capacitance retention.