Activated hierarchical porous carbon as electrode membrane accommodated with triblock copolymer for supercapacitors

Homopolymer PAN and triblock copolymer PAN- b -PMMA- b -PAN synthesized by RAFT polymerization were used to fabricate activated hierarchical porous carbon membranes by combining phase inversion , carbonization , and HNO 3 activation method; during the preparation process, a lot of micro- and meso-pores generated because of phase separation of PAN and microphase separation of PAN- b -PMMA- b -PAN. The hierarchical porous structure shortened ions transport paths and facilitated the rapid migration of electrolyte ions . When the polymer membrane was prepared by the casting solution with 5   wt% of PAN- b -PMMA- b -PAN and the electrochemical performance was tested at the current densities from 0.5 to 5   A   g −1 , a high-end specific capacitance of 297.0   F   g −1 and a capacitance retention of 75% were obtained in three-electrode configuration; this specific capacitance remained above 90% of initial value after 2000 cycles at 2   A   g −1 in 6   M KOH aqueous solution. Moreover, symmetric supercapacitors assembled with the prepared materials achieved high energy density (15.8   Wh   Kg −1 ) and power density (4000   W   Kg −1 ) in 1   M Na 2 SO 4 solution. The unique features and structures endowed the electrode membrane with good capacitive performance in both three-electrode and two-electrode configuration, which can be used as electrode membranes for high-performance energy storage devices and other applications.