Graphene recovered from used sensors can be reprinted five times without performance loss

The useful part

The team printed electrochemical sensors with the ink, then took them apart after use. They recovered more than 93% of the graphene, along with the solvent and the PET substrate, and used them to print new devices. The ink went through five consecutive recycling cycles without a drop in performance.

How it works

• Researchers at Silicon Austria Labs (SAL) and EPFL have developed a recyclable, surfactant-free graphene nanoplatelet (GNP) ink that uses linalool,a terpene alcohol that occurs naturally in lavender, basil...
• Schematic of the closed-loop recycling system: the graphene ink is used to print electrochemical sensors, and after recycling, the recovered material is reused to print new sensors and heaters.
• Communications Sustainability Most high-performance conductive inks still depend on petrochemical solvents such as NMP, DMF and toluene, several of which are classified as carcinogenic, mutagenic or reprotoxic.

Details worth keeping

They also use synthetic binders that make material recovery difficult. Earlier recycling approaches for printed electronics have typically recovered only part of a device, often by using corrosive solvents that destroy the substrate, or by reclaiming the conductive ink while leaving other layers contaminated.