One-Step Scalable Fabrication of Nitrogen and Chlorine Co-doped Graphene by Electrochemical Exfoliation for High-Performance Supercapacitors.

The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices. This study deploys a one-step, scalable, facile electrochemical exfoliation technique to fabricate nitrogen (N) and chlorine (Cl) co-doped graphene nanosheets (i.e., N–Cl–G) via the application of constant voltage on graphite in a mixture of 0.1 mol/L H₂SO₄ and 0.1 mol/L NH₄Cl without using dangerous and exhaustive operation. The introduction of Cl (with its large radius) and N, both with high electrical negativity, facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it. Consequently, in the as-constructed supercapacitors, N–Cl–G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7% retention of initial capacitance after 20,000 cycles at 10 A/g. Furthermore, a symmetrical supercapacitor assembled with N–Cl–G as the positive and negative electrodes (denoted as N–Cl–G//N–Cl–G) exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g. This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors. N, Cl co-doped graphene (i.e., N–Cl–G) is fabricated in situ via a one-step, scalable, facile electrochemical exfoliation process. Benefiting from the ultrathin nanosheet structure of N–Cl–G with large margin size and rich functional groups, the as-prepared N–Cl–G-based supercapacitor exhibits high specific capacitance and remarkable cycling stability. Precisely, the symmetrical N–Cl–G//N–Cl–G supercapacitor (N–Cl–G as both the positive and negative electrodes) exhibits high-energy density and superior cycling stability, highlighting its considerable potential for industrial application. [ABSTRACT FROM AUTHOR]