Growing spherical polypyrrole nanoparticles onto the magnetic carbon aerogel for improving electrochemical performance for supercapacitors

In this work, hierarchical porous magnetic activated carbon aerogels (aCA)/polypyrrole (PPy) composites were synthesized by a facile and cost effective in situ oxidation polymerization. Three-dimensional (3D) interconnected porous aCA with a high specific surface area (820.1 m2 g−1) was prepared by a sol–gel process via carbonization and KOH activation by using sodium carboxymethyl cellulose (CMC) and ferric trichloride as carbon precursors and cross-linking agents. The aCA served as a good skeleton for the growth of PPy particles on the surface. Via the cooperative effect of an interconnected porous network structure from aCA and the high capacitive property provided by PPy, the aCA/PPy electrode exhibited a high specific capacitance of 433 F g−1 at a current density of 0.5 A g−1. Moreover, it also exhibited outstanding long-period cycling performance of ~ 87.2% capacitance retention after 5,000 cycles of consecutive charge/discharge tests. Additionally, the asymmetric supercapacitor demonstrated high energy density of 2.59 W h kg−1 at the power density of 1266 W kg−1. This work provides a novel path for preparing aCA/PPy composites with great potential as a candidate high performance electrode material on energy storage.