Flexible free-standing vertically aligned carbon nanotube on activated reduced graphene oxide paper as a high performance lithium ion battery anode and supercapacitor

Here, controlled growth of vertically aligned carbon nanotubes (VACNTs) on free-standing porous activated reduced graphene oxide (a-rGO) paper was fabricated using plasma-enhanced chemical vapor deposition method. The electrochemical performance of prepared film was investigated to provide effective electrode for 3D flexible high-performance lithium-ion batteries (LIBs) and supercapacitors. The results revealed that the prepared electrode exhibited a high specific capacitance of 347 F/g at 0.5 A/g in 1 M KOH electrolyte, 60% more than non-activated rGO-paper (218 F/g). The VACNTs on a-rGO have increased the accessible surface area and acted as efficient electrical conducting paths, which improved the power density. The free-standing flexible supercapacitor fabricated using such a film exhibited a sufficient electrochemical behaviour with high power density of 407 kW kg−1 at 5 Wh.kg−1 at a current density of 0.5 A/g. Since VACNTs with low sp2 hybridization defect lead to cyclic stability, suitable for high-performance LIB anodes. This 3D flexible anode electrode demonstrated a high initial discharge capacity of 1401 mAhg−1 with a large reversible charge capacity of 958 mAhg−1 at 150 mAg−1. The charge and discharge capacity have reached a stable value of 459 mAhg−1 after 100 cycles with a coulombic efficiency of ∼100% which is much higher than most carbon structures.