Scalable Production of Graphene Nanoplatelets for Energy Storage

The difficulty of scaling up the production of high-quality graphene nanoplatelets remains a major challenge for the graphene community and inhibits commercialization across a variety of market segments and applications. Here, we demonstrate a compressed, permeable reactor that produces graphene nanoplatelets via electrochemical exfoliation and controlled pressure. In contrast to prior controlled-volume reactors, the second-generation reactor allows for both direct control of pressure on the graphite source and arbitrarily large batch sizes. We have measured how graphene production is affected by the electrode type and arrangement (working electrode and counter electrode), reactor dimensions, and reaction kinetics. The data indicate that the reactor must be thin in at least one dimension to avoid diffusion limitations, but the long dimension can be scaled up without decreases in the yield. As in other batch processes, the highest production rate occurs in the initial stage followed by a plateau in conversion. An expandable graphite feedstock results in a substantial increase in yield compared to graphite flake feedstocks under identical reactor conditions.