Materials Chemistry: Let it Snow

Researchers from the A*STAR Singapore Institute of Manufacturing Technology and Nanyang Technological University, Singapore, have developed tiny porous frameworks of zinc-antimony nanoflakes that could have a big impact on future hybrid vehicles and electronic devices.  The material, when deposited on copper foil, could enhance the charge-storage capacity and safety of lithium-ion batteries.  Most current lithium-ion batteries use graphite as the anode because it can retain its structure in the presence of lithium ions, giving the battery consistent charging behavior.  Graphite does, however, have a low charge-storage capacity, which limits the energy density of the battery, and, on rare occasions, the lithium metal can become intercalated into the graphite structure, which can cause the batteries to explode.  Using materials like zinc-antimony, with theoretically high charge-storage capacities, as anodes, could lead to thinner, lighter batteries that run at higher voltages, while also reducing lithium metal deposition.  Unfortunately, antimony-based alloys can result in early battery failure after repeated interactions with lithium ions.  The research team overcame the antimony problem by turning to nanotechnology, and developing a method to produce the zinc-antimony in a nanoflake structure.  The structure resulted in a steady discharge capacity one-third higher than commercial batteries that also could be recharged repeatedly without any structural changes.  According to researcher Bee Yen Tay, “The fast, easy and cheap fabrication of ZnSb nanostructures without a template makes it possible to prepare anodes with improved electrochemical performance using large-scale electroplating processes.  This system has the potential to form the basis for a new generation of lithium-ion batteries with higher energy densities.”

http://www.research.a-star.edu.sg/research/6317