New graphene fiber conducts heat better than copper while matching top carbon fiber strength

Researchers at Zhejiang University have developed a wet-spinning process that produces graphene fibers combining exceptional tensile strength with high thermal conductivity, addressing a long-standing trade-off between the two properties.

The team dispersed graphene oxide sheets in glycerol, a highly viscous solvent that gives the dispersion polymer-like viscoelastic behavior. That viscosity allowed the fibers to be stretched, or drawn, to a much higher ratio during wet spinning than previous methods have achieved, up to 11 times their original length. The ultrahigh-ratio drawing aligns the graphene oxide sheets closely along the fiber axis and compresses out internal voids and defects that have limited earlier graphene fibers. A subsequent high-temperature annealing step then grows large, aligned graphitic crystallites through the densely packed structure.