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 3 EMERGING TECHNOLOGY MORPHOGENIC CRYSTAL ACTUATORS Ledby researchers at the Advanced Science Research Center at the Grad- uate Center, CUNY (CUNY ASRC), New York, an international team is studying the development of shape-shifting crys- tals that directly convert evaporation energy into powerful motions. They created water-responsive materials by using simple variants of tripeptides to create crystals that are simultaneously stiff and morphable. The materials are composed of 3D patterns of nanoscale pores where water tightly binds, and those pores are interspersed with a molecular network of stiff and flexible regions. When humidity is lowered and reaches a critical value, water escapes from the pores, leading to a powerful contraction of the internal network. This results in the crystals temporar- ily losing their ordered patterns until humidity is restored and the crystals regain their original shape. This new process can be repeated over and over and gives rise to a remarkably efficient method of harvesting evaporation ener- gy to performmechanical work. The resulting morphogenic crys- tals are biocompatible, biodegradable, and cost-effective. By using a com- bination of laboratory-based experi- ments and computer simulations, the researchers were able to identify and study the factors that control the actu- ation of these crystals. This approach resulted in new insights that inform the design of more efficient ways to use evaporation for a variety of appli- cations, which may include robotic components or mechanical micro and nanomachines that are powered by wa- ter evaporation. asrc.gc.cuny.edu . LITHIUM BATTERY ALTERNATIVE A large team of scientists, led by the University of Warwick, U.K., is analyzing the prospect of sodium-ion batteries (NIBs) taking a lead role in the ener- gy storage market. NIBs offer a combination of attractive properties, including the use of sustainable precursors, a secure supply of raw materials, and cost- effectiveness. They are ENER Y TRE DS Graphic of NIB. Courtesy of University of Warwick. also considered a drop-in technology and could benefit from the already ex- isting lithium-ion battery (LIB) manu- facturing facilities. The scientists combined their knowledge and expertise to assess the current status of the sodium-ion tech- nology from materials to cell develop- ment, offering a realistic comparison of the key performance indicators for NIBs and LIBs. As with lithium-based systems, so- dium-based batteries come in different forms, such as sodium-ion and sodi- um-all-solid-state-batteries. One of the most important application fields for the NIB prototypes is stationary energy storage systems, where cost and cycle life represent two fundamental param- eters. Further technological improve- ments are needed to increase the per- formance, especially involving energy density. www.warwick.ac.uk . Momentum Technologies Inc., Dallas, licensed a process from Oak Ridge National Laboratory, Tenn., to recover cobalt and other metals from spent lithium-ion batteries. The company focuses on extracting critical metals from electronic waste. ornl.gov. BRIEF Illustration of tripeptide crystals, which feature aqueous pores that expand and contract in response to humidity changes. Courtesy of Tony Wang.