Feb_March_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 | F E B R U A R Y / M A R C H 2 0 2 0 1 5 EMERGING TECHNOLOGY BETTER, SAFER BATTERIES WITH LITHIUM DENDRITES An international team of research- ers has discovered a new way to study dendrites in lithium ion batteries. These structures often grow between elec- trodes and can cause fires and short circuits in the batteries. Scientists hope their newmethod will lead to important insights on preventing the dendrites’ destructive development. The collaborative research team from Georgia Tech, Penn State, and two universities in China successfully grew lithium whiskers inside an environmen- tal transmission electron microscope (ETEM) using a carbon dioxide atmo- sphere. The reaction of carbon dioxide with lithium forms an oxide layer that helps stabilize the whiskers. The team used an atomic force microscope (AFM) tip as a counter elec- trode and the integrated ETEM-AFM technique allows simultaneous imaging of the whisker growth, as well as mea- surement of the growth stress. “Now that we know the limit of the growth stress, we can engineer the solid electrolytes ac- cordingly to prevent it,” say the researchers. Lithium metal based all-solid-state batteries are desirable because of greater safety and higher energy density. psu.edu . CHEAPER AND GREENER THERMOELECTRIC MATERIALS The adoption of thermoelectric materials in varied industries has been slow due to the cost of processing. Now, researchers from Queen Mary Universi- ty of London have developed new low- cost thermoelectric materials to con- vert heat energy into electricity. The scientists conducted experi- ments on thin films of the halide per- ovskite, cesium tin iodide, to test its ability to create electrical current from heat. They were able to improve the materials’ thermoelectric properties through a combination of methods, which involved partial oxidation and the introduction of additional elements into the material. Thermoelectric technology has growing uses in domestic, commercial, and wearable applications, accelerating the need to find cheaper, non-toxic ma- terials that can also operate well at low temperatures. The researchers believe that halide perovskites could help satis- fy that demand. www.qmul.ac.uk . ENER Y TRE DS GEOTHERMAL STORAGE SYSTEM TEMPERS ELECTRICITY DEMAND Oak Ridge National Laboratory (ORNL), Tenn., researchers have de- veloped a geothermal energy storage system with inexpensive materials at a shallower depth. The system could reduce peak electricity demand up to 37% in homes and help balance grid operations. The system is installed under- ground and stores excess electricity from renewable resources like solar power as thermal energy through a heat pump. The system comprises un- derground tanks containing water and phase change materials that absorb and release energy when transitioning between liquid and solid states. The stored energy can provide hours of heating in the winter or cooling in the summer, shaving peak demand and helping homeowners avoid buying electricity at peak rates. ornl.gov. The U.S. Department of Energy (DOE) has launched the Energy Storage Grand Challenge, a comprehensive program to accelerate the development, commercialization, and utilization of next-generation energy storage technologies. The vision for the Energy Storage Grand Challenge is to create and sustain global leadership in energy storage utiliza- tion and exports with a secure domestic manufacturing supply chain that is independent of foreign sources of critical materials by 2030. energy.gov. BRIEF A lithium dendrite undergoes imaging and stress testing. Courtesy of Zhang Lab/Penn State. Geothermal energy storage system. Cour- tesy of Andy Sproles/ORNL/U.S. DOE.