Research progress in preparation and processing technology of C/SiC composites

Rare earth alloys can be prepared through the methods of melting, metallothermic reduction, and molten salt electrolysis. Compared to the former two methods, the molten salt electrolysis method has several advantages: the production cost is lower, the composition of the rare earth alloys is uniform and easy control, and the quality of the rare earth alloys is good. The rare earth alloys can be prepared easily and continuously on industrial scale. In this paper, the research progress in the molten salt electrolysis preparation of the rare earth alloys of magnesium, aluminum, iron, cobalt, nickel, and copper is reviewed by considering the rare earth alloy applications in structural, magnetic, and hydrogen storage materials. The prospects of the related research works are discussed.

Research progress in preparation, properties, and applications of medical protective fiber materials

Research progress in preparation of electrolyte for all-vanadium redox flow battery

Research progress in preparation of materials by joule heating method and its application in energy storage and conversion

Biochar is a carbonaceous material generated by pyrolysis of biomass under the condition of low oxygen content. Because of its large specific surface area, developed pore structure and rich oxygen-containing functional groups on the surface, it has a good adsorption and fixation effect on organic pollutants in soil, water and sediments. It is considered as an ideal and universal adsorption material and is widely used in the field of environmental pollution control. This paper reviews the preparation, application and defects of biochar. In order to provide reference value for the improvement of potential value and utilization rate of biochar.

Research progress in preparation and application of spinel-type metallic oxides (M≥2)

Research progress in preparation of conductive yarn and its application in smart wearable devices

The composition of hydroxyapatite (HA) is similar to human bone and teeth. After implantation into human body, its hydroxyl (OH) forms chemical bond with bone cells, and has good biological activity and biocompatibility. It is considered to be the best biomedical material for replacing human hard tissue. Electrophoretic deposition (electrophoretic deposition, EPD) is a new kind of coating preparation method, it can solve the traditional biological ceramic coating preparation technology on the various deficiencies, the paper introduced the domestic and foreign studies of hydroxyapatite coating of electrophoretic deposition. In this paper, the process flow of electrophoretic deposition method and the possible failure reasons are summarized, and various influencing factors are discussed in detail, and the corresponding ideas and prospects are put forward.

Research progress in preparation of hexagonal boron nitride aerogels and their applications in thermal conductivity and adsorption

Research progress in preparation of graphene and its composites based on ionic liquids

Research progress in preparation of metal powders by pressurized hydrogen reduction

Bioglass is a good bioactive material and has been used in many medical fields, include drug delivery systems, non-load-bearing implants and bone cements. Sol-gel is a good method in the preparation of coating materials. It also can be used in the preparation of bioactive glass. In this paper, the principles and technical processes are introduced. The effects on characteristics of bioactive glasses of the factors such as H2O dosage, ethanol dosage, gel temperature and activator are analyzed in detail. The research progress in preparation of sol-gel bioactive glasses is summarized. Finally the development foreground of sol-gel bioglass is also expected.

Aluminum powder is the most commonly used metal fuel in the industry of explosives and propellants. The research progress in preparation technology, reactivity and application of nano-aluminum in explosives and propellants is systematically reviewed in this paper. The preparation technology of nano-aluminum powder includes mechanical pulverization technology (such as the ball milling method and ultrasonic ablation method, etc.), evaporation condensation technology (such as the laser induction composite heating method, high-frequency induction method, arc method, pulsed laser ablation method, resistance heating condensation method, gas-phase pyrolysis method, wire explosion pulverization method, etc.), chemical reduction technology (such as the solid-phase reduction method, solution reduction method, etc.) and the ionic liquid electrodeposition method, each of which has its own advantages. Some new preparation methods have emerged, providing important reference value for the large-scale production of high-purity, high-quality nano-aluminum powder. The reactivity differences between nano-aluminum powder and micro-aluminum powder are compared in the thesis. It is clear that the reactivity of nano-aluminum powder is much higher than that of micro-aluminum powder in terms of ignition performance, combustion performance and reaction completeness, and it has a stronger influence on the detonation performance of mixed explosives and the combustion performance of propellants. Nano-aluminum powder is highly prone to oxidation, which seriously affects its application efficiency. In addition, when aluminum powder oxidizes or burns, a surface oxide layer will be formed, which hinders the continued reaction of internal aluminum powder. In addition, nano-aluminum powder may deteriorate the preparation process of explosives or propellants. To improve these shortcomings, appropriate coating or modification treatment is required. The application of nano-aluminum powder in mixed explosives can improve many properties of mixed explosives, such as detonation velocity, detonation heat, peak value of shock wave overpressure, etc. Applying nano-aluminum powder to propellants can significantly increase the burning rate and improve the properties of combustion products. It is pointed out that the high reactivity of nano-aluminum powder makes the preparation and storage of high-purity nano-aluminum powder extremely difficult. It is recommended to increase research on the preparation and storage technology of high-purity nano-aluminum powder.

Research Progress on Manganese Dioxide Electrode Materials for Electrochemical Capacitors

<p indent=0mm>As the key parts of the electrode, materials and structure design are the most important factors to determine the properties of supercapacitors. The structure design of the electrode plays a critical role in deciding its reaction kinetics, ion transportation, and consequently the electrochemical performance of energy storage system. Graphene, as a building block of sp² carbon materials, is characterized by large surface area, excellent electron transfer and great chemical stability, allowing it as the most promising material for energy storage and the results from many laboratories confirm its potential to change today’s energy-storage landscape. Typically, graphene-based materials are randomly oriented with respect to the current collectors in a conventional stacked geometry in supercapacitors. However, increasing the mass loading or film thickness seriously declines the charge storage capability, including specific capacitance and rate capability. This is mainly due to the moderate electrical conductivity, slow ion diffusion, and poor mechanical stability. Control of structure and morphology is key for carbon-based electrodes to allow the effective permeation of the electrolyte to establish electrical double layers in supercapacitors. Three-dimensional vertically aligned graphene (3DVAG) on the current collector is believed to provide an ideal structure for supercapacitors electrode capable of high energy density. 3DVAG electrodes have attracted much research interest owing to their excellent reaction kinetics and mass-transfer capability. The unique properties such as large surface area, vertical open channels and low pore tortuosity, can enhance the ion/electron transfer and increase mass loading of active materials, and thereby ultimately improves the rate capability and energy density of the electrode material. Compared with the traditional graphene-based electrode, 3DVAG electrode has short ion diffusion pathways, better electrochemical performance and also inherits the excellent cycle stability of graphene-based electrodes. At present, the main preparation methods of 3DVAG include directional freezing, plasma-enhanced chemical vapor deposition, KOH assisted hydrothermal and others (e.g.,<italic> </italic>rolling and cutting rGO, electric field deposition, magnetic field alignment). Through manipulating the preparation processes, 3DVAG materials with highly ordered microstructure, tight pore density and high conductivity will be obtained. In this contribution, we review the ongoing research progress in preparation of 3DVAG and its applications in supercapacitors. Firstly, the main preparation methods, the mechanism and the influence of process parameters on the texture of 3DVAG are emphasized. Secondly, the application of 3DVAG materials in the field of supercapacitors including double electric layer capacitors (EDLCs), the related composites for pseudocapacitors (SCs) and hybrid supercapacitors (HSCs) are highlighted. Finally, the challenges and opportunities of further development and application of 3DVAG materials are discussed. The purpose of this review is to introduce a new type of graphene structure with vertically aligned microtexture, providing ideas for the effective utilization of graphene, and with its good vertical channels, it provides a feasible solution for development of high mass loading and high energy density electrode materials.