Solid-state batteries are promising candidates for energy storage due to their potential advantages in safety, working temperature range, and energy density compared to traditional liquid-electrolyte-based batteries. Rational battery architecture design and a scalable fabrication approach are critical to realize solid-state batteries. In this article, we present the architecture, fabrication procedure, and related challenges of sulfide and oxide electrolyte-based solid-state batteries. Approaches toward intimate solid−solid contact, thin solid-electrolyte fabrication, and scale-up production are discussed. Finally, we discuss the future research directions of solid-state batteries.

Solid-state electrolytes can offer improved lithium-ion battery safety while potentially increasing the energy density by enabling alkali metal anodes. There have been significant research efforts to improve the ionic conductivity of solid-state electrolytes and the electrochemical performance of all-solid-state batteries; however, the root causes of their poor performance—interfacial reaction and subsequent impedance growth—are poorly understood. This is due to the dearth of effective characterization techniques for probing these buried interfaces. In situ and operando methodologies are currently under development for solid-state interfaces, and they offer the potential to describe the dynamic interfacial processes that serve as performance bottlenecks. This article highlights state-of-the-art solid–solid interface probing methodologies, describes practical limitations, and describes a future for dynamic interfacial characterization.

All-solid-state batteries utilizing a ceramic instead of an organic liquid as an electrolyte have the potential to be safer and more energy dense than traditional rechargeable lithium-ion batteries. This emergent energy-storage technology, however, is still critically limited by the performance of the solid electrolyte and its interface with electrodes. Here, we present a review of recent efforts in predictive modeling and materials design for lithium and sodium solid electrolytes using advanced computational approaches. These approaches have enabled the efficient design and discovery of new functional materials with desired properties, such as high alkali ionic conductivity, good phase and electrochemical stability, and low cost, accelerating the development of all-solid-state alkali batteries.

We report on reliability testing of vertical GaN (v-GaN) devices under continuous switching conditions of 500, 750, and 1000 V. Using a modified double-pulse test circuit, we evaluate 1200 V-rated v-GaN PiN diodes fabricated by Avogy. Forward current–voltage characteristics do not change over the stress period. Under the reverse bias, the devices exhibit an initial rise in leakage current, followed by a slower rate of increase with further stress. The leakage recovers after a day's relaxation which suggests that trapping of carriers in deep states is responsible. Overall, we found the devices to be robust over the range of conditions tested.

Among various methods used for the reduction of graphene oxide (GO) into a purer form of graphene, the thermal reduction method provides a simpler, safer, and economic alternative, compared to other techniques. Thermal reduction of GO causes significant weight loss and volume expansion of the material. Current work investigates the onset temperature where reduction in terms of exfoliation takes place, which is determined to be 325 °C at standard atmospheric pressure. Reduction temperature plays the most crucial role as it controls the quality of reduced graphene oxide in terms of weight percentage of carbon and lattice defect. The study leads to achieving highest content with a minimum defect in the graphene lattice at the optimum temperature, which is found to be 350 °C at standard atmospheric pressure. The thermal reduction process has been analyzed with the help of Fourier transform infrared spectroscopy, thermogravimetric analysis, and thermal degradation kinetics. From thermal degradation kinetics of GO, the rate of reaction has been found to be independent of concentration and is a sole function of temperature.

Herein, we report N, S co-doped carbon dots (NS CDs) as stabilizing and reducing agents for the synthesis of N, S doped carbon dots-Au nanocomposites (NS CDs-Au NCs) through the solution method and explore the catalytic property of the synthesized nanocomposites in the reduction of nitro aromatic compounds (NACs) such as 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and nitrobenzene (NB). The appraisal of the catalytic efficacy of the NS CDs-Au NCs was premised on real time monitoring of the reduction of NACs using UV-Visible absorption spectroscopy. The apparent rate constants (kapp) of reduction were found to follow the pseudo-first-order kinetics having values of 1.37 × 10−1, 8.9 × 10−2, and 5.35 × 10−2 s−1 for 4-NP, 4-NA, and NB, respectively. The apparent rate constant (1.37 × 10−1 s−1) observed for the reduction of 4-NP by NaBH4 using NS CDs-Au NCs has been found to be one of the highest values reported in the literature so far thereby validating their excellent efficacy as a catalyst.

The evolution of carbides and the coarsening behavior of L12 ordered γ′ phase in Ni–25Cr–20Co alloys aged for varying time from 1000 to 5000 h at 700 and 750 °C were discussed in this paper. The mechanical properties of the alloys after aging were also discussed. Due to the changing of predominated resistance factor, a few of the γ′ precipitates’ shape changed from spherical to cuboidal after aging at 750 °C for 3000 h. The sizes and volume fraction of the γ′ precipitates were measured after aging at both temperatures. The experimentally determined temporal exponent of the γ′ coarsening indicated that the coarsening kinetics is in accordance with both models: the classical matrix diffusion LSW model and the trans-interface diffusion-controlled model. Additionally, the coarsening rate of the γ′ precipitates is dominated by the diffusion coefficients of Nb based on the classical LSW model. Furthermore, the yield strength curves of the alloys aged at 700 °C showed different trends at both test temperatures which is related to the influence of γ′ coarsening on the critical resolved shear stress.

Fused deposition modeling (FDM) 3D printing is an additive manufacturing process capable of rapidly building three-dimensional computer-modeled objects. The technology offers an inexpensive and efficient technique to manufacture customized objects with intricate geometries using a simple printing process. However, FDM is currently restricted in application due to a limited availability of functional materials. Research in the field has focused on incorporating functional characteristics into printable polymers to expand application of FDM technology. In this work, neutron radiation shielding was targeted as an addition to FDM materials. By creating a composite material using a thermoplastic polymer matrix and boron nitride additive, neutron shielding of FDM-printed samples was enhanced from 50% attenuation in polymer specimens to 72% in composite specimens. The enhanced functionality of this new material enables FDM technology to be used in the manufacture of aerospace components, where neutron radiation presents a significant hazard.

The complex interaction between hematopoietic stem cells (HSCs) and their microenvironment in the human bone marrow ensures a life-long blood production by balancing stem cell maintenance and differentiation. This so-called HSC niche can be disturbed by malignant diseases. Investigating their consequences on hematopoiesis requires a deep understanding of how the niches function in health and disease. To facilitate this, biomimetic models of the bone marrow are needed to analyze HSC maintenance and hematopoiesis under steady state and diseased conditions. Here, 3D bone marrow models, their fabrication methods (including 3D bioprinting), and implementations recapturing bone marrow functions in health and diseases are presented.

Co–Cr alloys, more specifically L605, have superior mechanical properties and high-corrosion resistance, making them suitable materials for cardiovascular application. However, metallic materials for biomedical applications require finely tuned surface properties to improve the material behavior in a physiological environment. Oxygen plasma immersion ion implantation was performed on an L605 alloy, after an electropolishing pre-treatment. The oxidized layer was found to be rich in Co and O, it did not show any trace of Cr, and resulted in nanostructured. The corrosion properties were profoundly changed. Endothelial cells showed high viability after 7 days of contact with some modified surfaces.

The hydrogen embrittlement of 12Cr2Mo1R(H) steel at different strain rates were investigated after hydrogen precharging for 4 h in a 0.5 M H2SO4 solution with 2 g/L ammonium thiocyanate. Results showed that the embrittlement index increased and gradually reached a relative stable value of about 20% at the strain rate of 5 × 10−5 s−1 with the decrease of strain rates. SEM images depicted small and deep flakes at high strain rates, while flakes grew larger at slow strain rates. Most hydrogen-induced cracks (HICs) were transgranular fracture through lath grain of bainitic ferrite. High strain field surrounds the crack tips, which makes the crack tips of two close and parallel cracks deflect toward each another and even form crack coalescence. The electron backscatter diffraction technique was used to investigate the effects of grain boundaries, recrystallization fraction, kernel average misorientation map, texture component, and coincidence site lattice boundaries on the HIC propagation. High densities of dislocations and strain concentrations were found around the cracks, where grains are highly sensitive to HIC.