Nov_Dec_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 2 0 1 4 ZINC BATTERIES FOR ROBOTS A research team from the Univer- sity of Michigan, Ann Arbor, is integrat- ing a new rechargeable zinc battery into the structure of a robot to increase energy capacity. The approach will be particularly important as robots shrink to the microscale and below—scales at which current standalone batteries are too big and inefficient. Researchers say the combination of energy density and inexpensive materials means that the battery may already double the range of delivery robots. Applications for mobile robots continue to expand, from delivery drones to robotic nurses. On the micro side, researchers are exploring swarm robots that can self-assemble into lar- ger devices. Multifunctional structural batteries can potentially free up space and reduce weight, but until now they could only supplement the main battery. The new battery works by pass- ing hydroxide ions between a zinc electrode and the air side through an electrolyte mem- brane. That mem- brane is partly a network of aramid nanofibers and a new water-based polymer gel. The gel helps shuttle the hydroxide ions between the elec- trodes. Made with cheap, abundant, and largely non- toxic materials, the battery is more environmentally friendly than those currently in use. The gel and aramid nanofibers will not catch fire if the bat- tery is damaged, unlike the flammable electrolyte in lithium ion batteries. The strong aramid nanofiber net- work between the electrodes is the key to the relatively long cycle life for a zinc battery. And the inexpensive and re- cyclable materials make the batteries easy to replace. Beyond the advantag- es of the battery’s chemistry, the team says the design could enable a shift from a single battery to distributed en- ergy storage. umich.edu . NEW NANOMETRIC METALENS Researchers at the University of Sao Paulo developed a new metalens that can serve as a camera lens in smart- phones or be used in other devices that depend on sensors. The lens, which is a thousand times thinner than human hair, consists of a single nanometric layer of silicon on arrays of nanoposts that interact with light. The structure EMERGING TECHNOLOGY The recent expansion of Argonne National Laboratory’s Materials Engineer- ing Research Facility (MERF), Lemont., Ill., opened on September 10. The 28,000-sq-ft space now holds 50 scientists, engineers, and support staff who are developing scalable manufacturing technologies for advanced energy materials and chemicals. More than doubling its previous size, the new MERF will increase the capacity for researchers from Argonne, industry, other national labs, and academia to collaborate on manufacturing science and engineering. anl.gov. BRIEF Schematic of a structural Zn-air battery and its possible use in providing structure to a robot. Courtesy of Alice Kitterman/Sci. Robot. is printed by photolithography. Meta- lenses were first developed 10 years ago and achieve the highest resolution that is physically feasible, using an ultrathin array of tiny waveguides called a meta- surface that bends light as it passes through the lens. Based on the realization that in a conventional lens an increase in refrac- tion index increases the field of view in proportion to the flatness of the lens, the researchers designed a metalens to mimic a totally flat lens with an infinite refraction index, which could not be ob- tained with a conventional lens. Com- bining metalenses prevents super-res- olution, but the resolution obtained is sufficient for all conventional appli- cations. Testing the metalens with a 3D-printed camera produced high-reso- lution images with a wide field of view. www.eesc.usp.br/en. The lens can be used to produce high- resolution images with a wide field of view. Courtesy of Augusto Martins/USP.