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1 0 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 | M A R C H 2 0 2 2 that maximizes the battery’s perfor- mance. Until now, there’s never been a clear picture of what the SEI looks like when it’s saturated with electrolyte, as it would be in a working battery. Researchers from the DOE’s SLAC National Accelerator Laboratory at Stanford University, Menlo Park, Calif., made the first high-res images of this layer in its natural plump, squishy state. This advance was made possi- ble by cryogenic electron microscopy, or cryo-EM, a revolutionary technol- ogy that reveals details as small as atoms. According to the researchers, the results suggest that the right elec- trolyte can minimize the swelling and improve the battery’s performance— giving them a potential new way to tweak and improve battery design. It also provides scientists with a new tool for studying batteries in their every- day working environments. Next, the researchers say they’d like to find a way to image these materials in 3D, and to TESTING | CHARACTERIZATION WORLD’S FIRST FOR HARD MATERIALS A group of scientists from Peking University, China, invented a new instrument for high and low-tempera- ture mechanical analysis in the fields of superalloys, composites, functional materials, and amorphous alloys. The instrument is the world’s first dynamic mechanical analyzer (DMA) suitable for hard materials. It’s based on the elec- tro-mechanical impedance method which can quickly, accurately, and automatically measure Young’s modu- lus, shear modulus, and corresponding internal friction of materials under vari- able temperature conditions. Until now, there existed a lack of methods and instruments that could accurately measure material modulus and internal friction at the same time. Using their newDMA, the researchgroup obtained the grain boundary sliding internal friction peak in polycrystalline pure aluminum under high-frequency vibration (tens of kHz) for the first time, and the peak temperature reached nearly 500°C, which ismuch higher than the low-frequency in- ternal friction peak (285°C) discovered by metal physi- cist Ke Ting-sui in 1947. Next, they used the new DMA on titanium. The results of measuring the modulus and internal fric- tion of TC4 titanium alloy from room temperature to 1200°C using the new DMA show that near 990°C, both moduli reach the min- imum and both internal frictions peak, indicating that the material has under- gone a solid-state phase transition. https://en.coe.pku.edu.cn. HIGH-RES BATTERY PORTRAITS The race to develop lithium metal batteries for next-gen electric vehicles, electronics, and other uses has begun. But a central challenge remains—under- standing and manipulating a thin layer called the solid- electrolyte interphase or SEI, that forms when the electrolyte between battery electrodes corrodes the sur- face of the lithium metal anode. Although formation of SEI is believed to be inev- itable, researchers hope to stabilize and control the growth of this layer in a way Triangular holes make this material more likely to crack from left to right. Courtesy of N.R. Brodnik et al./ Phys. Rev. Lett. Instron, Norwood, Mass., announces a capacity expansion for its 3400 and 6800 series universal testing systems. The new systems are successors to the company’s 3300 and 5900 series and are available in force capacities to 300 kN. instron.com. BRIEF Hard material DMA based on electro-mechanical impedance method. Courtesy of Peking University College of Engineering. Left: Cryo-EM image of electrolyte clinging to holes in a sample grid shows excess electrolyte has formed crystals. Right: After blotting, the grid can clearly be seen and probed with beams of electrons. Courtesy of Weijiang Zhou/Stanford University.