Effect of topological structure on the supercapacitive performance of redox-active triblock copolymers electrode-based asymmetric supercapacitors

Abstract

In order to study the effect of topological structure of electrodes material on their supercapacitive performance, the different ratio of hydrophilic and hydrophobic moieties were designed in the redox-active triblock copolymers PFcn-b-PEG-b-PFcn (n = 10, 17, 28). And then, PFcn-b-PEG-b-PFcn coated on Ni foam (PFcn-b-PEG-b-PFcn/Ni, n = 10, 17, 28) was applied as electrode materials for supercapacitors. Result displaying that with the value n increased from 10 to 28, the specific capacitances of PFcn-b-PEG-b-PFcn increased. That is to say, the capacitive behaviors of PFcn-b-PEG-b-PFcn could be greatly regulated by topological structure. Among the three copolymers, the as-prepared PFc28-b-PEG-b-PFc28 possessed a specific capacitance up to 358 F g−1 calculated from discharge curve with current density 1 A g−1. Further, the cycle stability test for PFc28-b-PEG-b-PFc28 was performed and the results show that the capacitance decay is only 5% over 2000 cycles, indicating its long cycle life. The reasons for the high capacitance performance of PFc28-b-PEG-b-PFc28 are due to the ferrocenyl groups with a favorable redox environment and faster electron transport and better ion diffusion, which make the material fully utilized. Furthermore, PFc28-b-PEG-b-PFc28 was successfully used to assemble a simple asymmetric solid-state supercapacitor. In summary, the topological structure of the PFcn-b-PEG-b-PFcn effect on their supercapacitive performance, that is, with the value n increasing, their specific capacitances increase. Can be looked forward to, the PFcn-b-PEG-b-PFcn could be as promising candidates towards high performance electrodes for pseudocapacitive supercapacitors.