Achieving long cycle life for all-solid-state rechargeable Li-I2 battery by a confined dissolution strategy

Rechargeable Li-I2 battery has attracted considerable attentions due to its high theoretical capacity, low cost and environment-friendliness. Dissolution of polyiodides are required to facilitate the electrochemical redox reaction of the I2 cathode, which would lead to a harmful shuttle effect. All-solid-state Li-I2 battery totally avoids the polyiodides shuttle in a liquid system. However, the insoluble discharge product at the conventional solid interface results in a sluggish electrochemical reaction and poor rechargeability. In this work, by adopting a well-designed hybrid electrolyte composed of a dispersion layer and a blocking layer, we successfully promote a new polyiodides chemistry and localize the polyiodides dissolution within a limited space near the cathode. Owing to this confined dissolution strategy, a rechargeable and highly reversible all-solid-state Li-I2 battery is demonstrated and shows a long-term life of over 9000 cycles at 1C with a capacity retention of 84.1%.

Исследование реакции поверхности жидкости на импульсное воздействие наклонной газовой струи при малых числах Рэйнольдса

A mathematical description of the motion of a cavity on the liquid surface under an oblique action of a gas jet is obtained using the well-known expressions for the movement of a gas bubble in a liquid. The boundary of the viscous drag force domination over the form drag force is determined. The impingement of the gas jet on the liquid surface is considered as a dynamic object of the automatic control theory. It is found that the dynamic properties of the two-phase system "gas jet - liquid" are described by the integrator equations. Using a specially designed setup, the transient response of the "gas jet - liquid" system were experimentally obtained for the aerodynamic action at angles of 20º and 50º to the surfaces of liquids with the viscosities of 0.71 and 26.1 Pa•s (Reynolds number Re < 2). The research results are necessary for the analysis of the non-contact aerodynamic method of liquid viscosity measurements.

Extraction and Back-Extraction Behaviors of La(III), Ce(III), Pr(III), and Nd(III) Single Rare Earth and Mixed Rare Earth by TODGA

N,N,N′,N′-Tetraoctyl diglycolamide (TODGA), as a new extraction agent, is effective for its excellent performance and low environmental hazard, and it is very welcome for the rare earth separation process. In this paper, by controlling the extraction time, diluent type, acid type and its concentration, rare earth concentration, etc., the optimum extraction and back-extraction effects of TODGA on La(III), Ce(III), Pr(III), and Nd(III) and mixed rare earths were obtained. The experiment showed that 0.10 mol·L−1 TODGA had the best extraction effect on single rare earth under the conditions of using petroleum ether as diluent, 5 mol·L−1 nitric acid, 20 min extraction time, and 0.01 mol·L−1 rare earth. In the mixed rare earth extraction, the percentage concentrations of La(III), Ce(III), Pr(III), and Nd(III) could be achieved from 21.7%, 19.9%, 30.8%, and 22.2% at the initial stage to 90.5%, 37%, 51%, and 62% after extraction, respectively, by controlling the number of back-extraction cycles and the concentrations of hydrochloric acid and nitric acid in the back-extraction system. The TODGA–rare earth carrier system showed the best back-extraction effect when the hydrochloric acid concentration was 1 mol·L−1 and the back-extraction time was 20 min. At the same time, the mixed rare earth liquid system with low initial concentration was selected for extraction and separation of mixed rare earth. The separation effect was better, and the recovery rate was higher than that of mixed rare earth liquid system with a high initial concentration.

Ultrasonically Stir Cast SiO2/A356 Metal Matrix Nanocomposites

Metal matrix nanocomposites are a newly developed materials with promising applications in a wide variety of areas, ranging from medical to aerospace structures, owing to their lightweight high-strength properties. A light metal like aluminum is usually strengthened by a reinforcing agent of carbides, nitrides, oxides, carbon-based materials, or even elementals to boost the mechanical performance without sacrificing lightweight; however, almost all reinforcing nanomaterials are commonly poorly wetted by metals leading to agglomerations, clusterings, among other problems, with diminished ductility and overall mechanical performance. To tackle the mentioned problems, a number of strategies including coatings, thermal, mechanical, or chemical treatments may be followed. In the present study, a particular focus is paid on the mechanical dispersion of nano-silica particles in a molten A356 alloy through applying high-intensity ultrasonic agitations in order to improve dispersibility, wettability, and interfacial affinity. Nano-silica being an inexpensive high-strength nanomaterial is added to an A356 aluminum alloy melt and then dispersed and distributed by a 2-kW power ultrasonic system. Experimental results including microscopic observations and those mechanical experimentations revealed that the ultrasonication of the aforesaid solid–liquid system may greatly improve the affinity between the de-agglomerated nano-silica particles and the host aluminum matrix with enhanced ductility.

CALCULATION OF PHASE EQUILIBRIUM OF SYSTEM VAPOR–LIQUID IN TERNARY MIXTURES ISOAMYLOL–ETHANOL–WATER AND ISOBUTANOL–ETHANOL–WATER AT HIGH CONCENTRATIONS OF HIGHER ALCOHOLS

Проведено сравнение экспериментальных и расчетных данных при описании фазового равновесия по методам группового вклада UNIQUAC и NRTL для трехкомпонентных смесей изоамилол–этанол–вода и изобутанол–этанол–вода системы пар–жидкость при атмосферном давлении и высоких концентрациях высших спиртов (10–20% мас.). При расчете упругости паров чистых компонентов использовано уравнение Антуана. Приведены константы Антуана и парные энергетические параметры бинарного взаимодействия исследованных компонентов методов UNIQUAC и NRTL. Оба метода хорошо описывают равновесие в этих системах. The experimental and calculated data are compared in the description of phase equilibrium by the methods of the group contribution of UNIQUAC and NRTL for three-component isoamylol-ethanol-water and isobutanol-ethanol-water mixtures of the vapor-liquid system at atmospheric pressure and high concentrations of higher alcohols (10-20% by weight). The Antoine equation was used for calculation of the elasticity of vapors of pure components. The Antoine constants and the pairwise energy parameters of the binary interaction of the investigated components of the UNIQUAC and NRTL methods are given. Both methods well describe balance in these systems.

Dynamics of shock waves in bubble zones of finite size with a hydrate-forming gas

The purpose of this study is to study the dynamics of the wave field, which is realized in a channel with a liquid containing a rectangular zone with bubbles of the freon-12 hydrate-forming gas during the propagation of a pressure shock wave. In the initial state, the considered gas-liquid system is under pressure P0. After a sudden increase in pressure to the value of Pe, a pressure wave of a stepped profile propagates in the system and, as a result of the presence of a bubble curtain, its amplitude increases, which in turn has a more favorable effect on the formation of hydrate in gas bubbles. In the initial state, the hydrate formation process was not taken into account. As a result, the dynamics of the pressure wave is shown during its propagation in a semi-infinite channel containing a gas curtain with a hydrate-forming gas. The mechanism of gas hydrate formation is described in this work on the basis of the theory of nonequilibrium phase transitions in vapor-liquid systems.