A Continuous and Safe Strategy for Large-Scale Graphene Production by Electrochemical Exfoliation-Flexible Encapsulation Strategy and Array Electrolyzer

Developing low-cost and eco-friendly graphene preparation methods is the key to achieving large-scale industrial production and application. Electrochemical exfoliation is an emerging method for graphene production, but it is still limited to beaker-level research and lacks large-scale production strategies/devices. Herein, a flexible encapsulation strategy was proposed to design the anode/cathode electrode, and an array electrolyzer was developed to ensure the continuous and safe production of graphene for pilot-scale verification. The flexible encapsulation strategy can effectively improve the exfoliation efficiency and graphene yield up to 98.6 and 39.6% (layers <= 7, 97%), respectively, with a low I D/I G ratio of 0.22 and a high C/O ratio of 16.9. Severe carbon corrosion occurs during the scaled-up production due to the high temperature promoted hydroxyl radical formation and graphite size enlargement resulted tip effect. Both the H2O -> OH center dot route and SO4 2- -> S2O8 2- -> SO4 -center dot -> OH center dot route contribute to the formation of hydroxyl radicals and resulting carbon corrosion. As the electrolyte temperature decreases from 70 to 30 degrees C, the average carbon corrosion decreases dramatically from 75 to 46.7%. The scaled-up production of electrochemical exfoliation for graphene in this work demonstrates the feasibility of the flexible encapsulation strategy and array electrolyzer, showing great potential for further large-scale application.