Tunable synthesis of nanocarbon architectures and their application in advanced symmetric supercapacitors

摘要

Controllable fabrication of carbonaceous materials has aroused considerable interest, however, the development of template-free methods for the synthesis of nanocarbons with tunable architectures still remains a significant challenge in both experimental design and theoretical research. Herein, this study demonstrates the straightforward process for the selectively production of porous carbons nanoarchitectures including porous carbon microfibers (CMFs), carbon nanosheets (CNs) and carbon nanosheets decorated with hollow sphere (CNDHS) via a novel KNO3 activation process with cotton as the precursor. We found that not only the morphologies, but also the specific surface area and the pore size distributions of the products are drastically associated with the concentration of KNO3. In particular, the unique 2D nanosheets decorated with hollow spheres endow the CNDHS with large specific surface area (2091 m(2)/g), narrow micropores (1.38 nm), small internal resistance (0.87 Omega), and low level of heteroatoms content. Benefiting from the synergistic effects of these intrinsic features, the symmetric supercapacitors based on CNDHS display outstanding electrochemical performance including high specific capacitance of 183 F/g at 1 A/g, excellent rate capability of 62.8% at 50 A/g, small IR drop (0.735 V at 50 A/g), good cycling stability (91.1% of capacitance retention after 10,000 cycles) in 1 M TEABF(4)/AN electrolyte. Moreover, the proper integrated large energy density (28.875 Wh/kg) with high power density (37.125 kW/kg) demonstrated again that the present work may provide a new path for the design and production of various nanocarbon architectures for energy storage related applications. (C) 2018 Elsevier B.V. All rights reserved.