Impurities in graphene/PLA 3D-printing filaments dramatically influence the electrochemical properties of the devices.

Herein, for the first time, we report on the presence of metal impurities in a widely reported and commercially available graphene/polylactic acid (PLA) 3D-printing filament and discuss the influence of these impurities on the electrochemical properties of as-printed and modified electrodes with said filament. Our findings show that the graphene component of this commercial filament contains Fe, Ti and Al impurities.