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With the increasing demand for green energy due to environmental issues, developing batteries with high energy density is of great importance. Li-S batteries, since their big breakthrough in 2009, have attracted much attention in both academia and industry. In academia, significant progress has been made in improving the specific capacity, rate capacity, and cycle performance using various novel strategies. However, the performance is hugely different when these strategies are extended to mass production, indicating a significant difference between academic research, and industrial production. In this brief review, we discussed the gap between the academic research and commercialization in detail based on literature reports and to our more than 10 years' experience on Li-S pouch cells, which including cathodes, anodes, separators, interlayers, electrolytes, and additives. The problems, which existing in pouch cells by using the materials and technologies developed by academic research using coin cells, was analyzed. We expected that this review could be helpful to both academic research and industrial commercialization of Li-S batteries.

Effective protection from environmental degradation relies on the integrity of oxide as diffusion barriers. Ideally, the passivation layer can repair its own breaches quickly under deformation. While studies suggest that the native aluminum oxide may manifest such properties, it has yet to be experimentally proven because direct observations of the air-environmental deformation of aluminum oxide and its initial formation at room temperature are challenging. Here, we report in situ experiments to stretch pure aluminum nanotips under O gas environments in a transmission electron microscope (TEM). We discovered that aluminum oxide indeed deforms like liquid and can match the deformation of Al without any cracks/spallation at moderate strain rate. At higher strain rate, we exposed fresh metal surface, and visualized the self-healing process of aluminum oxide at atomic resolution. Unlike traditional thin-film growth or nanoglass consolidation processes, we observe seamless coalescence of new oxide islands without forming any glass-glass interface or surface grooves, indicating greatly accelerated glass kinetics at the surface compared to the bulk.

The formation of hollow-structured oxide nanoparticles is primarily governed by the Kirkendall effect. However, the degree of complexity of the oxidation process multiplies in the bimetallic system because of the incorporation of more than one element. Spatially dependent oxidation kinetics controls the final morphology of the hollow nanoparticles, and the process is highly dependent on the elemental composition. Currently, a theoretical framework that can predict how different metal elements result in different oxide morphologies remains elusive. In this work, utilizing a combination of state-of-the-art in situ environmental transmission electron microscopy and three-dimensional (3D) chemically sensitive electron tomography, we provide an in situ and 3D investigation of the oxidation mechanism of the Ni-Fe nanoparticles. The direct measurements allow us to correlate the 3D elemental segregation in the particles with the oxidation morphologies, that is, single-cavity or dual-cavity hollow structure, and multicavity porous structures. Our findings in conjunction with theoretical calculations show that metal concentration, diffusivity, and particle size are important parameters that dictate the mechanical and phase stabilities of the hollow oxide shell, which in turn determine its barrier properties and the final hollow oxide morphology. It sheds light on how to use multielemental oxidation to control morphology in nanomaterials and demonstrates the power of 3D chemical imaging.

Body-centred cubic (BCC) Ti-18Zr-13Mo (wt%) alloy displays excellent yield strength (≈ 800 MPa), stable hardening (rate > 1500 MPa) and uniform ductility > 18%, resulting from multi-TWIP (multiple twinning-induced plasticity) strengthening effect. This multimodal mechanisms include microscale {332} < 113 > deformation twinning (DT), nano-scale {112} < 111 > DT and a rare {5 8 11} < 135 > DT mode. Martensitic phase transformation is completely suppressed and the sample stays a single-phase solid solution throughout the deformation. In situ electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to characterize the multi-TWIP and dynamic Hall-Patch effect, with dislocation slip and large grain distortions at twin interfaces. IMPACT STATEMENT The addition of Zr solutes stabilizes β Ti-alloy and completely suppresses phase transformations, allowing {332} < 113 > , {112} < 111 > and {5 8 11} < 135 > multimodal twinning to give a better combination of strength, strain-hardening rate and ductility.

The effects of ionizing radiation on materials often reduce to "bad news". Radiation damage usually leads to detrimental effects such as embrittlement, accelerated creep, phase instability, and radiation-altered corrosion. Here we report that proton irradiation decelerates intergranular corrosion of Ni-Cr alloys in molten fluoride salt at 650°C. We demonstrate this by showing that the depth of intergranular voids resulting from Cr leaching into the salt is reduced by proton irradiation alone. Interstitial defects generated from irradiation enhance diffusion, more rapidly replenishing corrosion-injected vacancies with alloy constituents, thus playing the crucial role in decelerating corrosion. Our results show that irradiation can have a positive impact on materials performance, challenging our view that radiation damage usually results in negative effects.

No abstract

Targeted irradiation of nanostructures by a finely focused ion beam provides routes to improved control of material modification and understanding of the physics of interactions between ion beams and nanomaterials. Here, we studied radiation damage in crystalline diamond and silicon nanostructures using a focused helium ion beam, with the former exhibiting extremely longrange ion propagation and large plastic deformation in a process visibly analogous to blow forming. We report the dependence of damage morphology on material, geometry, and irradiation conditions (ion dose, ion energy, ion species, and location). We anticipate that our method and findings will not only improve the understanding of radiation damage in isolated nanostructures, but will also support the design of new engineering materials and devices for current and future applications in nanotechnology.