Facile synthesis of a Co3O4@carbon nanotubes/polyindole composite and its application in all-solid-state flexible supercapacitors

A supercapacitor electrode composed of a polyindole (PIn)-modified carbon nanotubes (CNTs) composite (CNTs/PIn) decorated with Co3O4 nanoparticles was synthesized to enhance the electrochemical performance. The PIn shell could improve the electric conductivity and the dispersion of CNTs, and the functional groups of PIn are conducive to anchoring the Co3O4 particles on the CNTs/PIn composite with large effective surface area, leading to a high specific capacitance of 442.5 F g−1. Moreover, the all-solid-state supercapacitor exhibits a high energy density (42.9 W h kg−1) at a power density of 0.4 kW kg−1 and excellent cycling performance (90.2% capacitance retention after 5000 cycles), demonstrating its promising application as an efficient electrode material for electrochemical capacitors.