posted on 2019-03-08, 19:33authored byChuanlong Li, Tahir Rasheed, Hao Tian, Ping Huang, Yiyong Mai, Wei Huang, Yongfeng Zhou
Controllable
preparation of porous hollow carbon spheres (HCSs)
has attracted considerable attention due to their potential applications,
e.g., in energy conversion and storage. We report for the first time
the synthesis of narrowly size-distributed HCSs with uniform micropores
in the wall, through a simple template-free approach, which employs
the solution self-assembly of an alternating copolymer (poly(9,9′-bis(4-glycidyloxyphenyl)fluorene-alt-2,3-dihydroxy-butylene dithioether) (P(BGF-a-DHBDT))). This alternating copolymer first self-assembled into previously
undocumented hollow polymeric spheres (HPSs) in an N,N-dimethylformamide (DMF)/H2O solvent
mixture. After the cross-linking of the BGF segments in the spheres,
the stabilized HPSs (CL-HPSs) were carbonized at 800 °C under
N2 atmosphere, yielding porous HCSs with uniform micropores
of very narrow size distribution (0.4–0.8 nm) in the wall,
benefiting from the uniform DHBDT block length in the alternating
copolymer. Through KOH activation, which made the internal pores fully
interconnected, uniform micropores (0.5–1.0 nm) of a narrow
size distribution were retained within the activated HCSs (A-HCSs),
while their specific surface areas (SSAs) were much increased to 2580
m2 g–1. As a proof of concept, the A-HCSs
were applied as electrode materials of supercapacitors. They exhibited
superior electrochemical performance with a high specific capacitance
(292 F g–1 at 0.2 A g–1), good
rate capability, and outstanding cycling stability with no apparent
capacitance loss after 10 000 cycles.