Chemical fabrication of a nanocomposite structure for electrode materials to regulate the ion diffusion channels and charge transfer resistances and Faradaic active sites is a versatile strategy towards building a high-performance supercapacitor. Here, a new ternary flower-sphere-like nanocomposite MnO2-graphite (MG)/reduced graphene oxide (RGO) was designed using the RGO as a coating for the MG. MnO2-graphite (MnO2-4) was obtained by KMnO4 oxidizing the pretreated graphite in an acidic medium (pH = 4). The GO coating was finally reduced by the NaBH4 to prepare the ternary nanocomposite MG. The microstructures and pore sizes were investigated by x-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and nitrogen adsorption/desorption. The electrochemical properties of MG were systematically investigated by the cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in Na2SO4 solution. The MG as an electrode material for supercapacitor exhibits a specific capacitance of 478.2 and 454.6 F g−1 at a current density of 1.0 and 10.0 A g−1, respectively. In addition, the capacitance retention was 90% after 8,000 cycles. The ternary nanocomposite enhanced electrochemical performance originates from the specific flower-sphere-like morphology and coating architecture bringing higher specific surface area and lower charge transfer resistance (Rct).

In this work, perovskite-type NdFeO 3 and NdCoO 3 nanofibers (NFs) were synthesized, and the magnetic and electrochemical characteristics of the two samples were investigated. The NdFeO 3 NFs showed ferromagnetic performance at 298 K and paramagnetic characteristics at low temperatures, whereas the NdCoO 3 NFs showed paramagnetic behavior. The NdFeO 3 and NdCoO 3 electrodes exhibited favorable electrochemical performance in supercapacitors and Li-ion batteries. Therefore, this study demonstrated the potential applications of NdFeO 3 and NdCoO 3 NFs in the field of condensed matter physics and energy storage devices.

The synthesis of a sustainable material through carbon nitride (C3N4) chemically grafted on waste-derived carbon including carbonizing coals (PM), melamine-urea-formaldehyde resins (MUF-C-1100), and luffa cylindrical sponges (SG), respectively, and its application as sulfur cathode in lithium-sulfur (Li-S) batteries were demonstrated. The Li-S cell assembled by the sulfur (S) cathode with component from C3N4 grafted coal-derived carbon (PM-CN) possesses a specific capacity of 1269.8 mA h g−1 at 0.05 C. At 1 C, the initial specific capacity of PM cathode is only 380.0 mA h g−1, comparable to the PM-CN5 cathode of 681.9 mA h g−1, and PM-CN10 cathode of 580.7 mA h g−1, respectively. And, PM-CN 5 cathode presents the capacity retention of 75.9% with a coulomb efficiency (C.E.) of 97.3% after 200 cycles. The MUF-CN cathode gives a specific capacity of 1335.6 mA h g−1 at 0.05 C, and the capacity retention of 66.7% with a C. E. of 93.6% after 300 cycles at 0.5 C. The SG-CN cathode had a specific capacity of 953.9 mA h g−1 at 0.05 C, and capacity retention of 95.1% with a C. E. of 98.2% after 125 cycles at 1 C. The remarkable improved performances were mainly ascribed to the sustainable materials as S host with micro-meso pore and C3N4 structure providing the strong affinity N sites to lithium polysulfides (LiPSs). This work provides an attractive approach for the preparation of sustainable materials by rational design of grafting C3N4 to waste-derived carbons with functions as S cathode materials for high-performance Li-S batteries.

Uniform perovskite type SmFeO3 and SmCoO3 nanofibers have been prepared by a simple electrospinning approach and calcination process. The obtained samples had orthorhombic structure and strong absorbance behaviors in UV‐vis regions. The diameters of SmFeO3 and SmCoO3 nanofibers were 220 and 300 nm, respectively. The electrochemical and magnetic properties of SmFeO3 and SmCoO3 were investigated. SmFeO3 and SmCoO3 electrodes exhibited typical pseudocapacitive behaviors owing to the redox reactions of Fe3+/Fe2+ and Co3+/Co2+. At 0.5 A g‐1, the specific capacitances of SmFeO3 and SmCoO3 nanofibers were 90.8 and 126.6 F g‐1, respectively. The high‐performance nanostructured SmFeO3 and SmCoO3 have significantly potential application in supercapacitors. SmFeO3 nanofibers exhibited weak ferromagnetic behavior. SmCoO3 nanofibers presented paramagnetism at high temperature and ferromagnetism at 5 K.