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Category: materials – Page 238

Researchers create new zinc-air pouch cells

Zinc-air batteries (ZABs) are among the most promising next-generation battery technologies due to their many advantageous characteristics. Most notably, these batteries have unique half-open structures, a significant theoretical energy density (1086 and 1370 Wh kg−1 when including and excluding oxygen, respectively), flexible electrodes and an inherently aqueous electrolyte. Moreover, in contrast with other materials used in batteries, Zinc (Zn) is less harmful for the environment and more abundant.

Researchers at Hanyang University in South Korea recently designed a new type of zinc-air pouch cell that can outperform other commercially available battery technologies. These pouch cells, presented in a paper published in Nature Energy, use (101)-facet copper phosphosulfide [CPS(101)] as a cathode, anti-freezing chitosan-biocellulosics as super-ionic conductor electrolytes, and patterned Zn as the anode.

“Previous ZABs employing liquid (6 M KOH) electrolytes failed because of the sluggish kinetics for the oxygen reduction and evolution reactions (ORR/OER) and irreversibility of Zn accompanying the parasitic reactions over wide temperatures,” Jung-Ho Lee, one of the researchers who carried out the study, told Tech Xplore. “This feature inspired us to develop solid-state electrolytes, such as functionalized biocellulose, capable of transferring OH- ions effectively without parasitic reactions.”

Strange “Black Swan” Defect Discovered in Soft Matter for First Time

Using an advanced microscopy technique, Texas A&M researchers have uncovered a twin boundary defect in a soft polymer that has never been observed before.

Texas A&M University scientists have for the first time revealed a single microscopic defect called a “twin” in a soft-block copolymer using an advanced electron microscopy technique. This defect may be exploited in the future to create materials with novel acoustic and photonic properties.

“This defect is like a black swan — something special going on that isn’t typical,” said Edwin Thomas, professor in the Department of Materials Science and Engineering. “Although we chose a certain polymer for our study, I think the twin defect will be fairly universal across a bunch of similar soft matter systems, like oils, surfactants, biological materials, and natural polymers. Therefore, our findings will be valuable to diverse research across the soft matter field.”

Unexpected ‘Black Swan’ defect discovered in soft matter for first time

In new research, Texas A&M University scientists have for the first time revealed a single microscopic defect called a “twin” in a soft-block copolymer using an advanced electron microscopy technique. This defect may be exploited in the future to create materials with novel acoustic and photonic properties.

“This defect is like a black swan—something special going on that isn’t typical,” said Dr. Edwin Thomas, professor in the Department of Materials Science and Engineering. “Although we chose a certain polymer for our study, I think the twin defect will be fairly universal across a bunch of similar soft matter systems, like oils, surfactants, and natural polymers. Therefore, our findings will be valuable to diverse research across the soft matter field.”

The results of the study are detailed in the Proceedings of the National Academy of Sciences (PNAS).

Advance may enable 2D transistors for tinier microchip components

Moore’s Law, the famous prediction that the number of transistors that can be packed onto a microchip will double every couple of years, has been bumping into basic physical limits. These limits could bring decades of progress to a halt, unless new approaches are found.

One new direction being explored is the use of atomically instead of silicon as the basis for new transistors, but connecting those “2D” materials to other conventional electronic components has proved difficult.

Now researchers at MIT, the University of California at Berkeley, the Taiwan Semiconductor Manufacturing Company, and elsewhere have found a new way of making those , which could help to unleash the potential of 2D materials and further the miniaturization of components—possibly enough to extend Moore’s Law, at least for the near future, the researchers say.

Harvard researchers develop long-lasting solid-state battery

To combat this, Li and his team at Harvard have designed their solid-state battery with a multilayer approach that stacks its materials of varying stabilities between the anode and cathode. Much like a sandwich. This multi-material battery sandwich helps alleviate the penetration of lithium dendrites by controlling and containing them rather than preventing them altogether.

As you can see from the image above, the Harvard team has simplified its battery design to a form that’s more our speed. In this case, a BLT sandwich. The top slice of bread represents the lithium-metal anode, followed by lettuce appropriately representing a coating of graphite. The two layers of tomatoes represent the first electrolyte, protecting the delicious middle layer of bacon as the second electrolyte. Everything sits upon the bottom slice of bread, or the cathode. Is anyone else suddenly hungry for batteries?

In this design, dendrites are able to grow through the graphite (lettuce) and first electrolyte (tomato) but are halted when they reach the second electrolyte (bacon), thus preventing the dendrites from shorting the entire battery. This multilayer approach provokes chemistry that makes the second electrolyte too tight for the dendrites to penetrate. Furthermore, the Harvard researchers say this same chemistry can backfill the holes made by dendrites, essentially making the solid-state battery self-healing. Is there anything better than a sandwich that can regenerate itself? Honestly.

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