Sustainable up-cycling of spent electric vehicle anodes into solution processable graphene nanomaterials

Abstract

A major transition to electric vehicles (EVs) is underway globally, as countries target reductions in greenhouse gas emissions from the transport sector. As this rapid growth continues, significant challenges remain around how to sustainably manage the accompanying large volumes of waste from end-of-life lithium-ion batteries that contain valuable rare earth and critical materials. Here, we show that high-shear exfoliation in aqueous-surfactants can up- cycle spent graphite anodes recovered from an EV into few-layer graphene dispersions. For the same hydrodynamic conditions, we report a process yield that is 37.5% higher when using spent graphite anode as the precursor material over high purity graphite flakes. Increasing surfactant concentration, the average atomic layer number reduces in a similar way to high purity precursors. We find that the electrical conductance of few-layer graphene produced using the graphite flake precursor is superior, and identify the limitations when using aqueous-surfactant solutions as the exfoliation medium for spent graphite anode material. Using these non-toxic solution processable nanomaterial dispersions, functional paper-based electronics were fabricated, illustrating the potential for end-to-end, environmentally sustainable up-cycling of spent EV anodes into new technologies.