Lithium-ion batteries have had a profound impact on our daily life, but inherent limitations make it difficult for Li-ion chemistries to meet the growing demands for portable electronics, electric vehicles and grid-scale energy storage. Therefore, chemistries beyond Li-ion are currently being investigated and need to be made viable for commercial applications. The use of metallic Li is one of the most favoured choices for next-generation Li batteries, especially Li-S and Li-air systems. After falling into oblivion for several decades because of safety concerns, metallic Li is now ready for a revival, thanks to the development of investigative tools and nanotechnology-based solutions. In this Review, we first summarize the current understanding on Li anodes, then highlight the recent key progress in materials design and advanced characterization techniques, and finally discuss the opportunities and possible directions for future development of Li anodes in applications.

Reviving the lithium metal anode for high-energy batteries

We have developed a transparent organic polymeric material that can repeatedly mend or "re-mend" itself under mild conditions. The material is a tough solid at room temperature and below with mechanical properties equaling those of commercial epoxy resins. At temperatures above 120 degrees C, approximately 30% (as determined by solid-state nuclear magnetic resonance spectroscopy) of "intermonomer" linkages disconnect but then reconnect upon cooling, This process is fully reversible and can be used to restore a fractured part of the polymer multiple times, and it does not require additional ingredients such as a catalyst, additional monomer, or special surface treatment of the fractured interface.

https://science.sciencemag.org/content/sci/295/5560/1698.full.pdf

A Thermally Re-mendable Cross-Linked Polymeric Material

Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within our environment safely and effectively. Interest in large-area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large-area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e-skin) akin to human skin. E-skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self-powering). Continued rapid progress in this area is promising for the development of a fully integrated e-skin in the near future.

25th Anniversary Article: The Evolution of Electronic Skin (E-Skin): A Brief History, Design Considerations, and Recent Progress

PEEK Biomaterials in Trauma, Orthopedic, and Spinal Implants

Hydrogenation is a core technology in chemical synthesis. High rates and selectivities are attainable only by the coordination of structurally well-designed catalysts and suitable reaction conditions. The newly devised [RuCl(2)(phosphane)(2)(1,2-diamine)] complexes are excellent precatalysts for homogeneous hydrogenation of simple ketones which lack any functionality capable of interacting with the metal center. This catalyst system allows for the preferential reduction of a C=O function over a coexisting C=C linkage in a 2-propanol solution containing an alkaline base. The hydrogenation tolerates many substituents including F, Cl, Br, I, CF(3), OCH(3), OCH(2)C(6)H(5), COOCH(CH(3))(2), NO(2), NH(2), and NRCOR as well as various electron-rich and -deficient heterocycles. Furthermore, stereoselectivity is easily controlled by the electronic and steric properties (bulkiness and chirality) of the ligands as well as the reaction conditions. Diastereoselectivities observed in the catalytic hydrogenation of cyclic and acyclic ketones with the standard triphenylphosphane/ethylenediamine combination compare well with the best conventional hydride reductions. The use of appropriate chiral diphosphanes, particularly BINAP compounds, and chiral diamines results in rapid and productive asymmetric hydrogenation of a range of aromatic and heteroaromatic ketones and gives a consistently high enantioselectivity. Certain amino and alkoxy ketones can be used as substrates. Cyclic and acyclic alpha,beta-unsaturated ketones can be converted into chiral allyl alcohols of high enantiomeric purity. Hydrogenation of configurationally labile ketones allows for the dynamic kinetic discrimination of diastereomers, epimers, and enantiomers. This new method shows promise in the practical synthesis of a wide variety of chiral alcohols from achiral and chiral ketone substrates. Its versatility is manifested by the asymmetric synthesis of some biologically significant chiral compounds. The high rate and carbonyl selectivity are based on nonclassical metal-ligand bifunctional catalysis involving an 18-electron amino ruthenium hydride complex and a 16-electron amido ruthenium species.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1521-3773%2820010105%2940%3A1%3C40%3A%3AAID-ANIE40%3E3.0.CO%3B2-5

Asymmetric Catalysis by Architectural and Functional Molecular Engineering: Practical Chemo‐ and Stereoselective Hydrogenation of Ketones

5414 - fatigue of self-healing polymers: multiscale analysis and experiments

The well-known Taylor cylinder impact test, that follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, PTFE and PEEK. In previous work experiments and a model were developed to capture the deformation behaviour of the rod after impact. A distinctive feature of these works was that a region in which both spatial and temporal variation of both longitudinal and radial deformation showed evidence of changes in phase within the material. This region is X-ray imaged in a range of impacted targets at the I13 Imaging and Coherence beam line at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. This shows the transit of damage from ductile to brittle failure results from previously undetected internal failure.

/pdf/on-compression-and-damage-evolution-in-ptfe-and-peek-4j585jd429.pdf

On compression and damage evolution in PTFE and PEEK

Racemic total syntheses of isoaustrobailicnan-1 and of some related aryltetralin lactones

Fatigue of self-healing polymers

This year marks the 75th Anniversary of the Society for Experimental Mechanics (SEM). In 1943 the Society for Experimental Stress Analysis (SESA), the forbearer of SEM was born out of a meeting of the Eastern Photoelastic Conference [1]. While the 1943 meeting was formally the Seventeenth Semi-Annual Eastern Photoelastic Conference and Experimental Stress Symposium, the Conference Executive Committee included numerous luminaries leading the much broader field of Experimental Mechanics including William M. Murray, Thomas J. Dolan, Miklos Hetenyi, Charles Lipson, Raymond D. Mindlin, Elmer K. Timby, F. G. Switzer, and E. O. Waters. Murray, Hetenyi and Lipson proposed that a dues-paying organization be formed with a focus beyond any one particular technique. Along with R. D. Mindlin, they formed the organizing group for the new society and went on to serve as the first four presidents. Lipson worked for the Engineering Institute of the Chrysler Corporation which hosted the conference and funded the Conference Proceedings that became Volume 1 Number 1 of the SESA Proceedings. The society continued to be known as SESA through the 1984 Fall meeting in Milwaukee, WI [2] and took on the current name of the Society for Experimental Mechanics with the 1985 Spring SEM meeting in Las Vegas, NV [3]. Lipton opened that first 1943 meeting with [4]:

/pdf/celebrating-75-years-of-the-society-for-experimental-4f83qshhvt.pdf

Eric Brown

Papers

5414 - fatigue of self-healing polymers: multiscale analysis and experiments

On compression and damage evolution in PTFE and PEEK

Racemic total syntheses of isoaustrobailicnan-1 and of some related aryltetralin lactones

Fatigue of self-healing polymers

Celebrating 75 Years of the Society for Experimental Mechanics and the Study of Dynamic Behavior of Materials