Graphitic carbon nitride is an ordered two-dimensional stability. However, its bulk structure with low electrical conductivity (less than 1 S cm-1) restricts the applications in electrochemical energy storage. This is because conventional synthesis methods lack effective thickness control, and the excessive nitrogen doping (∼50%) leads to poor electrical conductivity. Here, we report an ultrathin conductive graphitic carbon nitride assembly (thickness of ∼1.0 nm) through graphene-templated van der Waals epitaxial strategy with high electrical conductivity (12.2 S cm-1), narrow pore-size distribution (5.3 nm), large surface area (724.9 m2 g-1), and appropriate nitrogen doping level (18.29%). The ultra-thin structure with nitrogen doping provided numerous channels and active sites for effective ion transportation and storage, while the graphene layers acted as micro current collectors; subsequently, it exhibits high energy storage capability of 936 mF cm-2 at 1 mA cm-2 with excellent stability of over 10 000 cycles. Moreover, the all-solid-state supercapacitors showed an ultra-high energy density of 281.3 μWh cm-2 at 1 mA cm-2 with high rate capability, Coulombic efficiency, and flexibility. This work represents a general framework for the bottom-up synthesis of ultrathin 2D materials, which may promote the application of graphitic carbon nitride in energy storage. © 2019 American Chemical Society.
Bibliographical noteThis work was supported by the Yonghong Zhang Family Center for Advanced Materials for Energy and Environment and startup funding by Columbia University and AFOSR (grant no. FA9550-18-1-0410).
- flexible supercapacitors
- Graphitic carbon nitride
- ultra-thin structure
- van der Waals epitaxy