Ultrafast alternating-current exfoliation toward large-scale synthesis of graphene and its application for flexible supercapacitors

To facilitate the transition of laboratory research to industrial applications, it is critical to establish a reliable protocol for the mass synthesis of high-quality graphene. Here, we present an efficient electrochemical intercalation-based exfoliation approach utilizing alternating current that allows for the production of subkilogram quantities of graphene. This strategy involves repeatedly intercalating foreign anions and cations into the interlayer gaps of dual-graphite electrodes, accelerating the graphite expansion process and maximizing the exfoliation efficiency of both electrodes while inhibiting excessive anodic oxidation. The exfoliation process leads to high-yield graphene nanosheets (92 %, primarily 1-3 layers) with minimal structural deterioration (ID/IG ratio of 0.05), high purity (2.1 at% oxygen), and outstanding electrical property (7.28 x 104 S m-1). Notably, our scaled-up manufacturing technique produces a record-breaking throughput of 135 g h-1, improving on the bestreported exfoliation efficiency with direct current by 35%. Furthermore, the as-made graphene demonstrates a large reversible capacity of 102 mF cm-2 for flexible supercapacitors, with robust cyclability with 99.5% after 10,000 cycles, excellent mechanical flexibility, and exceptional serial integration for adjustable voltage output. The efficient and scalable method presents a significant advancement in the large-scale manufacture of graphene, with potential for widespread industrial applications.

Automated summary

In this study, an efficient electrochemical intercalation-based exfoliation method was proposed to synthesize high-quality graphene on a large scale. The method produced high-yield graphene nanosheets with high purity and excellent electrical properties. By improving the manufacturing technique, the production efficiency was significantly increased, and the cycling performance was excellent. The development of this method is of great significance for large-scale manufacture and industrial applications of graphene.