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Biomass carbon-based MnO electrode materials were synthesized using ramie as the biomass precursor of carbon and potassium permanganate as the precursor of MnO. The ramie-activated carbon/manganese monoxide (RAC/MnO) composite electrodes exhibited a specific capacitance of 720 F/g at a current density of 0.5 A/g. A symmetric cell assembled using the composite electrodes showed a specific capacitance of 45 F/g at 0.5 A/g and an energy density of 12.25 Wh/kg at a power density of 350 W/kg. The excellent electrochemical performance was analyzed by characterizing the electrodes' chemical composition, microstructure, crystal orientation, specific surface area, and pore distribution. Because of the large overpotential of MnO, the composite electrode's working voltage reached 1.4 V, which is 40% higher than 1.0 V of traditional carbon electrodes. As such, supercapacitors can have higher energy density and power density with the RAC/MnO composite electrodes. The experimental equipment for synthesizing the electrodes is very simple and is promising for large-scale commercialization. [ABSTRACT FROM AUTHOR]

• AlCuNiTiZr high entropy alloy films deposited by magnetron sputtering • AlCuNiTiZr films showing excellent anti-corrosion properties • A scheme of a reasonable equivalent electrical circuit proposed In this study, corrosion-resistant AlCuNiTiZr high-entropy alloy (HEA) films were deposited by direct current magnetron sputtering. The films were found to be amorphous. Corrosion resistance of the films in 0.5 M H 2 SO 4 solution were investigated and compared with 316L stainless steel. The minimum corrosion current density of the HEA films was about one order of magnitude lower than that of 316L stainless steel. The inductively coupled plasma optical emission spectra showed that the concentrations of Cu, Ni, Ti and Zr ions in the corrosion solution were as low as 10−7 mol / L, while the concentration of Al ions was 7.5×10−6 mol / L. It is revealed that two passivation layers were formed on the surface from electrochemical impedance spectroscopy and equivalent electrical circuit, and the passivation layers resulted in protective effect on the AlCuNiTiZr HEA films in the sulfuric acid solution. [ABSTRACT FROM AUTHOR]

• NiS Sodium lignosulfonate. • Activated carbon Composite electrode materials. • Cycle life Asymmetric supercapacitor. In this paper, NiS nanoparticles had been successfully loaded on activated carbon (AC) derived from sodium lignosulfonate via hexadecyl trimethyl ammonium bromide assisted hydrothermal method. Due to synergistic effects of AC and NiS nanoparticles, the conductivity of the NiS/AC electrode is significantly improved, and the composite electrode exhibits a high specific capacity (677 C/g at 0.5 A g−1) and excellent rate performance. Moreover, an asymmetric supercapacitor (ASC) device was assembled with the NiS/AC composite as positive electrode and the AC as negative electrode to evaluate the electrochemical performance of NiS/AC composites in practical applications. The ASC device achieves a maximum energy density of 45.6 Wh/kg at a power density of 509.5 W/kg, and excellent cycling stability with 92.6% of capacitance retention after 20,000 cycles. The electrochemical performance suggests that NiS/AC composites have great application prospect as electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

Abstract: There is the complex relationship between Poisson's ratio and time in viscoelastic solids. Hence, using a simple model to characterize accurately the viscoelastic Poisson's ratio is important for the analysis of viscoelastic behaviors. We put forward two deformation elements, fractional and spring deformation element, and obtain three fractional deformation models through connecting the two deformation elements in parallel or series. The functions of viscoelastic Poisson's ratio are also derived for stress relaxation and constant-longitudinal-strain loading. Further comparisons between tests and fitting results reveal that the fractional deformation models can represent reasonably the viscoelastic Poisson's ratio. [Copyright &y& Elsevier]