1. Self-supporting electrode of N, O co-doped activated carbon nanofibers derived from hydroxyl-functionalized polyimides for supercapacitors.
- Author
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Zheng, Wenyue, Lu, Yunhua, Pan, Dongying, Xiao, Guoyong, Wang, Yongqi, Zhao, Hongbin, and Hu, Zhizhi
- Subjects
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ACTIVATED carbon , *POLYIMIDES , *DOPING agents (Chemistry) , *CARBON nanofibers , *SUPERCAPACITOR electrodes , *SUPERCAPACITORS , *ENERGY density - Abstract
The hydroxyl-functionalized poly (amic acid) (PAA) is first synthesized from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP) and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and electrospun into nanofibers. Then, the PAA nanofibers are thermally imidized at 300 °C and rearranged at 450 °C, followed by an ultimate carbonization to obtain hydroxyl-functionalized polyimide (HPI) based carbon nanofibers (CNFs). When the PAA concentration and carbonization temperature are respectively optimized as 28 % and 800 °C, the obtained CNF specimen HPI(6FAP-6FDA)-28-800 exhibits a better electrochemical performance, with a specific capacitance of 226.3 F g−1 at 0.5 A g−1. Subsequently, the HPI(6FAP-6FDA)-28-800 is subjected to KOH activation treatment. When the CNF/KOH mass ratio is 1/3, the activated sample CNF(6FAP-6FDA)-1/3 displays a maximum specific capacitance of 354.0 F g−1, coupled with a high rate-performance of 75 % (10 A g−1). Furthermore, a button-type supercapacitor (SC) assembled by two pieces of self-supporting CNF(6FAP-6FDA)-1/3 membrane attains an energy density maximum of 11.39 W h kg−1 at a power density of 250 W kg−1. Under 10,000 cycles of charging-discharging, the SC demonstrates an outstanding working stability. In brief, this study reports a novel polymer precursor for the preparation of N, O co-doped active CNFs, and provides an insight into the relationship between the chemical structure, microstructure and electrochemical performance for self-supporting SC electrodes. • The N, O co-doped activated carbon nanofibers were prepared. • The o -hydroxyl polyimides containing rich –C(CF 3) 2 - structures were used as precursors. • The self-supporting electrodes exhibited superior capacitive performances. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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