Fabricating of N/O-codoping porous carbon interpenetrating networks for high energy aqueous supercapacitor

Abstract

Developing high-capacity carbon electrodes with an enlarged potential window is a significant strategy for high energy aqueous supercapacitor. However, engineering synthesis of hierarchical porous carbon networks with the broad electrochemical stability window remains a great challenge. In this work, N/O codoped hierarchical porous carbon networks (MPBx) are constructed based on Schiff-base reaction for the purpose of excellent charge storage and kinetics of electrolyte ions diffusion in “water-in-salt” (lithium bis(trifluoromethane sulfonyl)imide, LiTFSI) electrolyte. When fabricated as an electrode for symmetrical supercapacitor, the 2.25 V LiTFSI-based supercapacitor exploits a superior specific capacitance (180 F g−1, 0.5 A g−1) and an exceptional energy delivery of 31.7 W h kg−1 at the corresponding power output of 562 W kg−1, together with an impressive cycling stability with 93.8 % capacitance retention after 10,000 continuous cycles. The improvement in the superb electrochemical performance can be attributed to the excellent conductive networks, high ion-adsorption area (1902 m2 g−1), interpenetrating porous architecture (macro-, meso- and micropore) and high-level heteroatoms dopants (N: 2.56 at.%, O: 11.46 at.%). The excellent electrochemical performances demonstrate that the carbon networks hold great prospects for promoting the energy delivery of aqueous supercapacitors.