Materials: Spinning weaves large and small graphene platelets into aligned fibers with excellent properties

Graphene’s thinness coupled with its extraordinary strength and capacity to conduct heat and charge has driven researchers worldwide to study ways of using the thin-film material in electronics and other applications. But those exceptional properties typically do not show up in macroscopic graphene samples, such as fibers. Now, a team led by Jie Lian of Rensselaer Polytechnic Institute (RPI) has demonstrated a simple method for making graphene fibers with outstanding strength and thermal conductivity, paving the way to exploiting graphene in high-power electronics and tough composites (Science 2015, DOI: 10.1126/science.aaa6502). Unlike previous efforts, in which researchers formed fibers exclusively from relatively large graphene flakes, in the new study, the RPI team used a wet-spinning method to intercalate small graphene platelets (<1 μm diameter) into the voids of a fiber backbone made from well-aligned large flakes (~25 μm diameter). After heat-treating the fibers, the team measured their properties and found that they are stronger than fibers made exclusively from large graphene flakes. They also transport heat better than large-flake graphene fibers, commercial carbon fibers, and copper wires.