Dual Halogen Doping of Graphene With Chlorine and Bromine via Electrochemical Exfoliation for High‐Performance Flexible Supercapacitors

Abstract

Supercapacitors attracted great attention for their expeditious charge and discharge rates and splendid cyclic stability. The doping of heteroatoms into graphene (G) can alter the electronic configuration of carbon atoms, alleviating the stacking problem of G‐based materials. This work focused on a one‐step green scalable electrochemical exfoliation strategy for the rapid preparation of high‐quality thin‐layer G nanosheets with double halogen doping. The as‐made chlorine (Cl) and bromine (Br) dual‐doped graphene (Cl/Br‐G) nanosheets exhibited a transparent feature with a large lateral size. Density functional theoretical calculations indicated that the introduction of Cl and Br can not only enlarge the interlayer spacing of graphene but also produce the charge distribution through the formation of delocalized π bonds in the defect region. The flexible micro‐supercapacitor (MSC) constructed with Cl/Br‐G as the electrodes demonstrated remarkable charge storage performance and impressive mechanical flexibility. In particular, the Cl/Br‐G‐MSC displayed much higher specific capacitance and long‐term cycling stability for 300,000 cycles compared with the single‐doping counterparts. This innovative approach to dual halogen doping in G holds significant promise for energy storage, and the electrochemical exfoliation technique offers valuable insights for producing other two‐dimensional layered materials.