The plasma facing components, first wall, and blanket systems of future tokamak-based fusion power plants arguably represent the single greatest materials engineering challenge of all time. Indeed, the United States National Academy of Engineering has recently ranked the quest for fusion as one of the top grand challenges for engineering in the 21st century. These challenges are even more pronounced by the lack of experimental testing facilities that replicate the extreme operating environment involving simultaneous high heat and particle fluxes, large time-varying stresses, corrosive chemical environments, and large fluxes of 14-MeV peaked fusion neutrons. Fortunately, recent innovations in computational modeling techniques, increasingly powerful high-performance and massively parallel computing platforms, and improved analytical experimental characterization tools provide the means to develop self-consistent, experimentally validated models of materials performance and degradation in the fusion energy environment. This article will describe the challenges associated with modeling the performance of plasma facing component and structural materials in a fusion materials environment, the opportunities to utilize high-performance computing, and two examples of recent progress.

Energy storage can help integrate wind and solar power into the electric grid.

Future energy production and storage in the chemical and refinery industries, stationary power generation, and transportation sectors will employ a diverse suite of technologies, including renewables, such as biomass, untapped energy resources, and processes with improved energy efficiency. Heterogeneous nanocatalysts will play an ever-increasing role in these technologies. Increased precision in molecular architecture over multiple length scales and/or tailored multi-functionality will often be needed in these materials. Advances in computational-based discovery of such nanomaterials are described through examples that predict the molecular architecture of emergent catalytic materials and reveal mechanisms of colloidal metal nanoparticle growth.

Energy storage is a critical hurdle to the success of many clean energy technologies. Batteries with high energy density, good safety, and low cost can enable more efficient vehicles with electrified drive trains, such as hybrid electric vehicles, electric vehicles, and plug-in hybrid electric vehicles. They can also provide energy storage for intermittent energy sources, such as wind and solar. Today, and for the foreseeable future, rechargeable lithium batteries deliver the highest energy per unit weight or volume at reasonable cost. Many of the important properties of battery materials can be calculated with first-principles methods, making lithium batteries fertile ground for computational materials design. In this article, we review the successes and opportunities in using first-principles computations in the battery field. We also highlight some technical challenges facing the accurate modeling of battery materials.

The three-dimensional structure of crack tip dislocations in single crystal silicon was observed by combining high-voltage electron microscopy and tomography. It was revealed that dislocations cross-slipped proximal to the crack tip even in the initial stages of plastic deformation. The local stress intensity factor along the crack front was calculated by taking into account the experimentally determined dislocation character. Based on these observations and calculations, a model to account for the sequential multiplication of dislocation sources along the crack front is proposed.

Spinning carbon nanotube (CNT) thread directly from 4–6 mm long aligned carbon nanotube arrays is reported here. The strength of carbon nanotube thread was improved by optimizing the chemical vapor deposition parameters for growing long aligned carbon nanotube arrays. The morphological and structural characterization of CNT arrays and threads were studied by Raman spectroscopy, transmission electron microscopy, and scanning electron microscopy. After optimization of growth parameters threads were spun with diameters between 10 and 70 μm. We have achieved thread strength of about 280 MPa.

We have developed a new class of proton-conducting organic–inorganic hybrid silicophosphite membranes, produced by ethanol condensation of organically modified alkoxysilanes and anhydrous vinylphosphonic acid under solventless, catalyst-free, low-temperature, one-pot conditions. The membranes synthesized in this study are crack-free, large, and flexible, and they exhibit good thermal stability up to intermediate temperatures (~218 °C). Structural analyses using 29Si and 31P nuclear magnetic resonance spectroscopy and infrared measurements revealed that ethanol condensation produced an inorganic alternating copolymer structure, Si–O–P, with a phosphole group, and successive polymerization between vinyl and/or methacryl groups enabled these structures to connect with each other. In this way, it is possible to achieve structure manufacturing of inorganic–organic networks. The proton conductivities of the hybrids are as high as 5.2 × 10−3 S/cm at 85 °C under 80% relative humidity.

Polycrystalline BaTiO3 thin films have been prepared by hydrothermal reaction with sputter-deposited nanostructured reactive Ti templates designed to control net diffusion direction and distance. Templates were prepared in two morphologies, i.e., planar and nanopillar. The samples produced from flat templates showed sluggish transformation kinetics and an eventual termination of reaction without fully consuming the Ti metal. Templates with pillar morphology, on the other hand, could be transformed to phase-pure BaTiO3, independent of the template thickness. In the as-precipitated state, those films revealed a permittivity of ~1000 and loss tangent values around 0.1 with mild dispersion in the kilohertz frequency range. Annealing these films under forming gas containing 1 vol% H2 balance N2 for 3 h at 200 °C decreased high-field losses to 0.06 and reduced dispersion. Mn incorporation as an in situ acceptor dopant was also explored. Addition of Mn during hydrothermal treatment further improved the electrical properties. Annealing under the same postgrowth conditions virtually eliminated the frequency dispersion in the range of 1 kHz to 1 MHz, while maintaining permittivity values in the range of 350.

Mn-doped γ-Ga2O3 thin films with a defective spinel structure have been epitaxially grown on spinel (100) substrates using pulsed laser deposition. The crystal quality of the films is strongly dependent on preparation conditions, particularly substrate temperature and laser energy density, as well as Mn concentration. In the 7 cation% Mn-doped film grown under the optimized conditions, the full width at half maximum in the x-ray diffraction rocking curve for the (400) plane is 117 arcsec and the root-mean-square roughness of the surface is approximately 0.4 nm. These values are comparable to those of the spinel substrate. The film shows a uniform tetragonal distortion with a tetragonality of 1.05.

Weak-beam dark-field images of dislocations interacting with particles acquired over a large angular range were used to reconstruct tomograms, which were then used as the basis to construct a three-dimensional (3D) model of the dislocation structure. These capabilities facilitate viewing the dislocation structure from different directions, recovering the information lost in the electron beam direction. Coupling these capabilities and a method to include the specimen coordinate system within them with conventional dislocation analysis enables a full characterization of the dislocation microstructure in three dimensions. This approach is used to understand the 3D nature of the interaction of dislocations and a twist boundary with Al3Sc particles in an Al–Mg–Sc alloy.

Upon rapid heating to a high temperature (~800 °C), mixtures of nitrate compounds and urea created nano and submicron metal particles. The process (reductive/expansion synthesis, RES) results in atomic scale mixing. The product formed from mixed-nitrate (Fe + Ni) salts and urea created true metallic alloy. Unlike other product-from-powder synthesis processes, this process produced only zero valent metal. Initial work suggests this method is a scalable and efficient means for making metallic nanoparticles. Although this is primarily a phenomenological report, a preliminary model is presented: Initially, nitrates decompose to oxide; thus in the absence of urea metal oxide particles form, as in the case of combustion synthesis. In the case of urea/nitrate mixtures, there is a “convolution” of decomposition processes. Urea decomposes to yield reducing gases, leading to the formation of metal rather than oxide. Rapid “expansion” of gas leads to “shattering,” resulting in highly dispersed particles.