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 ID/IG 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• route and SO42– → S2O82– → SO4–• → OH• route contribute to the formation of hydroxyl radicals and resulting carbon corrosion. As the electrolyte temperature decreases from 70 to 30 °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.