In this study, we provide a simple and green approach to recycle waste zinc carbon batteries for making carbon dots and porous carbon material. The carbon dots are easily synthesized by one green step, the hydrothermal treatment of a carbon rod in a mixture of DI water and pure ethanol to obtain a blue fluorescence under UV light, which can be used directly as a fluorescence ink. The as-prepared carbon dot process give typical dots with a uniform diameter from 3 to 8 nm with a strong slight blue fluorescent. The porous carbon material is also recycled from carbon powder in a waste battery via one green step annealing process without any chemical activation and with a hierarchically porous structure. This porous carbon material is demonstrated as an electrode for symmetrical solid state supercapacitors (SSCs) in a sandwich structure: porous carbon/PVA–KOH/porous carbon. The SSCs using recycled porous carbon electrodes exhibit a good energy density of 4.58 W h kg⁻¹ at a power density of 375 W kg⁻¹ and 97.6% retention after 2000 cycles. The facile one green step of hydrothermal and also that of calcination provide a promising strategy to recycle waste zinc carbon batteries, which transfers the excellent applications.

Kitchen sea salt or table salt is used every day by cooks as a food seasoning. Here, it is introduced into a gel polymer (poly(vinyl) alcohol (PVA)-table salt) for use as an electrolyte, and an electrode was constructed from graphene nanosheets for use as symmetrical solid-state supercapacitors. The graphene sheets are prepared by a pulse control plasma method and used as an electrode material, and were studied by X-ray diffraction (XRD), Raman spectroscopy, as well as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). A specific capacitance of 117.6 F g⁻¹ at 5 mV s⁻¹ was obtained in a three electrode system with table sea salt as an aqueous electrolyte. For a symmetrical solid-state supercapacitor: graphene/PVA-table sea salt/graphene gave a good specific capacitance of 31.67 F g⁻¹ at 0.25 A g⁻¹ with an energy density of 6.33 W h kg⁻¹ at a power density of 600 W kg⁻¹, with good charge–discharge stability, which was 87% after 8000 cycles. Thus, the development of table sea salt as an environmentally friendly electrolyte has a good potential for use in energy storage applications.

This work reports molecular beam epitaxy of two-dimensional GaSe_1−xTe_x ternary alloys that have recently attracted a lot of interest in physics and material sciences even though facing crucial challenges in their epitaxial technology.

The magnetic hybrid structure of a half-metallic ferromagnetic oxide and a non-magnetic oxide is promising for future spintronic devices. However, the ferromagnetic layer’s structural and magnetic characterizations must be improved urgently. Here, we report on the effect of annealing time on enhancing the structural and magnetic properties of Fe3O4 films. Radio-frequency magnetron sputtering was used to fabricate Fe3O4 thin films on a multilayer of MgO/Ta/SiO2 at room temperature. As-grown Fe3O4 samples were annealed at the optimal temperature for various times. The structural and magnetic properties of Fe3O4 were observed by using atomic force microscopy, X-ray diffraction, and a vibrating sample magnetometer. The structural characterization of Fe3O4 thin films is significantly enhanced when increasing the annealing time. Moreover, the magnetization of Fe3O4 thin films is also highly improved compared to the bulk value. Our finding provides a highlight for the next generation of spintronics.