Hydrogen is an alternative energy source to achieve decarbonization. However, storage and transportation costs are expensive. Hydrogen carriers are attracting attention for cost-effective hydrogen production, and ammonia is the most promising material. This article explores the potential of sustainable hydrogen production through ammonia decomposition using various plasma sources with/without catalysts, and compares the hydrogen production efficiency including dielectric barrier discharge(DBD), microwave plasma, and gliding arc discharge. Additionally, we evaluate the technology readiness levels(TRLs) of these plasma processes compared to other existing ammonia decomposition technologies such as only catalytic methods and electrolysis. The results reveal the advantages and limitations of each source in terms of energy efficiency and scalability. In addition, we suggest the possibility of thermal plasma for the large-scale hydrogen production. Our findings provide valuable insights into the feasibility and practical implementation of plasma technologies for sustainable hydrogen production, contributing to the advancement of clean energy solutions and the reduction of global carbon emissions.

The growing environmental concerns due to increased fossil fuel consumption have intensified the demand for sustainable and economically viable energy sources. Among the various energy storage devices, lithium-ion batteries (LIBs) are widely used in electronic devices and electric vehicles due to their high energy density and excellent cycle life. However, LIBs face challenges such as safety concerns due to side reactions, thermal expansion, and explosion risks, along with issues of limited resource availability and high costs. As a result, multivalent metals such as calcium, magnesium, zinc, iron, and aluminum are being explored as alternatives to lithium. Recently, there has been significant interest in developing aqueous zinc-ion battery (AZIB) due to their use of water as an electrolyte solvent, which enhances safety by reducing the risk of fire even in the event of a short circuit. Additionally, AZIBs offer benefits such as non-toxicity, fast ion conductivity, high volumetric capacity, and cost-effectiveness due to the abundance of zinc. Despite these advantages, AZIBs face challenges including dendrite formation on the zinc anode during cycling, leading to short circuits, corrosion, and hydrogen gas evolution, which can compromise battery performance and safety. This review discusses the underlying mechanisms of these issues and explores various strategies to stabilize the zinc anode and improve the overall performance of AZIBs.

Al-Ag thin films with varying compositions were fabricated using a combinatorial sputtering system to develop highly sensitive SAW devices. The Al-Ag sample library exhibited a wide range of electrical resistivity and chemical compositions, providing valuable data for selecting optimal materials. Recognizing the significant influence of both resistivity and density of IDT electrodes on the generation of acoustic waves from piezoelectric materials, three types of Al-Ag thin films with different Al contents were fabricated, maintaining a consistent thickness of 150 nm. As the Al content decreased from 84.6 at% to 21.7 at%, the resistivity increased from 5.1 to 0.8 × 10^-5 Ω-cm, while the calculated density increased from 3.9 to 8.8 g/cm³. The SAW devices fabricated with these Al-Ag IDT electrodes resonated at 71 MHz without frequency shifts, but the resonant frequency selectivity and insertion loss deteriorated with decreasing Al content, highlighting the predominant influence of electrode density over electrical conductivity on SAW device performance.

Chrome plating is a method used to protect the inside of a gun barrel from the severe environment (3,000 K and 4,000 MPa for 20 ms) created by the propellant gas when a cannon is fired. However, Cr-plated films have physical limitations, and the formation of hexavalent Cr compounds has a harmful effect on the environment. Ta-W alloy film has been explored as an alternative to Cr plating owing to the high melting point and corrosion resistance of Ta. However, obtaining pure α-phase Ta by sputtering is difficult, and the autofrettage effect in gun barrels limits the use of annealing. Therefore, a deposition method without the use of additional heat treatment is required to prepare Ta-W films with alpha-phase Ta. We explored the feasibility of depositing Ta-W alloy film inside a 2,800 mm-long stainless-steel tube using bipolar high-power impulse magnetron sputtering. A specially designed cylindrical magnetron sputtering equipment and a four-stage experimental process was employed to deposit a coating with uniform thickness (10.59%) throughout the tube, high adhesive strength (51.51 MPa), and pure alpha-phase Ta. The findings of this study are useful for deposition of Ta-W alloy films inside large-caliber canons.

In this study, ZnO nanoparticle treatments were applied to stainless steel 304 to mitigate the generation of stress corrosion cracking (SCC) under pressurized water reactor (PWR)-simulated conditions, focusing on temperature and pressure (300℃, 150 bar), specifically simulating temperature and pressure. ZnO nanoparticles were synthesized via plasma discharge in an aqueous solution, with sizes ranging from 355 ± 142 nm to 25.7 ± 7.2 nm along the long axis, controlled by adjusting the voltage parameters. After treatment with 25 nm ZnO nanoparticle treatment, the surface of stainless steel 304 was analyzed using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), confirming the formation of a compact and dense ZnCr₂O₄ spinel oxide film with a thickness of approximately 65 nm. Corrosion potential tests conducted using a Potentiostat/Galvanostat revealed that corrosion resistance improved as ZnO nanoparticle size decreased. Additionally, U-bend tests under accelerated corrosion conditions showed significantly reduced SCC in samples treated with 25 nm ZnO nanoparticles. These findings suggest that ZnO nanoparticles synthesized via plasma discharge could be effectively applied for SCC mitigation in the nuclear industry.

Using DC magnetron sputtering, we deposited a bilayer composed of a seed layer consisting of Ti, Cr, Co, and Zr, and an overlayer of Ag on MgO(001) single crystal substrates, creating self-assembled nanostructures. When Ti was used as the seed layer, it was observed that the formed nano-dots inherently aggregated into dot shapes. Additionally, Cr, Co, and Zr were chosen to investigate their influence on SLAA(Seed layer Assisted Agglomeration) depending on the seed layer material, revealing different shapes of the formed nano-dots. Moreover, it was observed that aggregation was inhibited as the thickness of the seed layer exceeded a critical point. X-ray diffraction analysis of the Ti seed layer revealed epitaxial growth of Ag along the (001) direction of the MgO substrate. In contrast, no epitaxial growth was observed when Cr, Co, and Zr were used as seed layer materials. Ultimately, Ti was identified as the most suitable seed layer material for the fabrication of self-assembled nanostructures utilizing the aggregation phenomenon of the bilayer. This research is deemed sufficiently valuable in addressing the limitations associated with the low productivity and high cost of current nano thin film processes.

Supercapacitors as energy storage devices require specific capacitance and rate capability improvements to achieve high energy and power densities. Activated carbon, commonly used as an electrode for supercapacitors, should have a porous structure for high capacitance and the large mesopores for high power. This study aims to produce mesoporous carbon for supercapacitors from the mixture of polyvinylidene chloride-resin (PVDC-resin) precursor and ZnO activating agent at a controlled mixing ratio via heat treatment. To synthesize porous carbon with high specific capacitance and high rate performance, PVDC-resin and ZnO were mixed in various ratios and activated at 950℃. Analysis of the pore structure and surface area of the synthesized carbon samples showed that the specific surface area and the amounts of micropores and mesopores also increased with more ZnO agents. Notably, the porous carbon synthesized from PVDC-resin to ZnO at a 2:3 ratio exhibited a high specific capacitance of 125 F g^-1 and excellent rate performance of 74%, demonstrating its potential as an optimal supercapacitor electrode material based on its surface area and mesoporous structure. This study identifies the optimal mixing ratio of PVDC-resin precursor and ZnO activator for the economical and efficient synthesis of activated carbon.

As demand in the electric vehicle market increases, the development of high capacity, high energy density lithium-ion batteries (LIBs) is required. Silicon has a extremely high theoretical capacity of 4200 mAh/g, but low cycle life and structural instability due to high volume expansion during charging and discharging are critical issue to solve. A reduced silicon oxide has also a high theoretical capacity of 2500 mAh/g and recently studied extensively for its low-cost, superior cycle life, and structural stability. In this study, we first synstheized SiO₂ particles by sol-gel method using tetraethyl orthosilicate (TEOS) precursor. The SiO₂ particle size was controlled with an average particle size of 300-600 nm by the addition amount of TEOS, NH₃, and H₂O. The synthesized SiO₂ particles were reduced to SiO_x through the magnesiothermic reduction reaction (MRR), and electrochemical characteristics were evaluated according to the particle size of SiO_x. For electrochemical characterization, SiO_x (10 wt.%) was mixed with graphite, and 2032 half cells were fabricated to obtain charge-discharge curve, cycle performance, rate performance, and electrochemical impedance spectroscopy curves. As a result, the mean size of SiO_x particle decreases from 600 to 300 nm, the initial discharge capacity increases from 459.9 to 556.5 mAh/g with the single capacity from 1359.4 to 2325.3 mAh/g, respectively. Finally, the present result shows the availability of MRR process to obtain reduced silicon oxide particles and sized dependent electrochemical properties to develop high capacity and high energy density LIBs.