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The hierarchical nanohoneycomb-like CoMoO4–MnO2 core–shell and Fe2O3 nanosheet arrays on 3D graphene foam (GF) are reported and explored their use as a binder-free electrode in supercapacitor applications.

Problem statement: In this study, attempts had been made to synthesize silver (Ag)/Poly Vinylpyrolidone (PVP) nanoparticles by ionizing radiation and at the same time overcoming some of the disadvantages previously reported by other methods such as impurities, solvent toxicity, size and distribution control and difficulty in their preparation that limits their commercialization potential. Approach: The use of this alternative method overcomes some unfavorable characteristics like long tedious and costly process, uncontrolled size and distribution. The advantages of radiation processing of the materials relative to other methods are; no metallic catalyst is required; (gives pure product), no oxidizing or reducing agent is required, the process occurs at a liquid or/and solid-state condition, fast and inexpensive, environmental friendly with controllable acquisitions. Results: Ag/PVP nanoparticles were successfully prepared in one-step by γ-irradiation technique in an aqueous system at room temperature and under ambient pressure. The Transmission of Electron Microscopy (TEM) of the as-prepared product particles ranged from 100 to around 8 nm depend on the irradiation dose value, which showed a good distribution with a controlled size as dose changed. The presence of PVP polymer was considered as an important reason that influenced the shape and distribution. The band gap energy was calculated from the UV-VIS absorption spectra. Thermal analysis TGA showed that the composite had a higher degradation temperature than the PVP alone. Conclusion: This result indicated that AgNO₃ can effectively dope PVP and enhance the optical and thermal properties. In addition, γ-irradiation is an effective technique for preparing inorganic/organic nanocomposites

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Supercapacitors possess minimum energy density, lower rate capability, and inferior long-term cycling stability performance, and these issues have restricted their practical applications. In these circumstances, supercapacitors based on a new class of hybrid nanomaterial are strongly desirable. Herein, for the first time, a complex nanoarchitecture comprised of a ZnS−Ni 7 S 6 /Ni(OH) 2 core/shell is constructed via a multistep hydrothermal process. The ZnS−Ni 7 S 6 / Ni(OH) 2 core/shell nanoarchitecture illustrates a commendable areal capacitance of 13.55 F cm −2 at a lower current density value of 5 mA cm −2 , respectively. The ZnS−Ni 7 S 6 /Ni(OH) 2 core/shell hybrid nanomaterial maintains a high cycling stability performance of 95.12% after a maximum 10 000 number of cycles. Moreover, the asymmetric supercapacitor device made up of ZnS−Ni 7 S 6 /Ni(OH) 2 and nitrogen−sulfurcodoped graphene nanosheets (NSGNs) delivers an ultrahigh energy density value of 68.85 W h kg −1 at a power density of 700.16 W kg −1 . The cycling stability of the ZnS−Ni 7 S 6 /Ni(OH) 2 //NSGN asymmetric supercapacitor was performed and was 91.79% after 10 000 GCD cycles. The ZnS−Ni 7 S 6 /Ni(OH) 2 core/shell hybrid electrode material has helped in promoting an asymmetric supercapacitor device with an elevated performance and can be considered as a potential electrode material to develop energy storage devices in the future.

There is an increasing demand for current and future applications to obtain charge storage devices with both energy and power superiority. Recently, several high-rate pseudocapacitive anode materials in Li-ion batteries...

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