One-step electrodeposition synthesis of high performance carbon nanotubes/graphene-doped Ni(OH)2 thin film electrode for high-performance supercapacitor

In this work, we successfully synthesized Ni(OH)2 thin film electrode in situ doped with CNTs/rGO by cathodic electrodeposition on titanium mesh. The doping effects of CNTs and/or rGO, and the technical conditions, are investigated. The doping of CNTs/rGO can greatly improve the electrochemical performance by forming the porous structure and the conductive network in the Ni(OH)2 thin film. The highest capacity, 429.5 mAh/g at a current density of 5 A/g, is achieved for the electrode with 0.24 mg/cm2 Ni(OH)2 and codoped with CNTs and rGO, as compared with only 323.9 mAh/g for undoped electrode. Even at 100 A/g, the specific capacity can still remain 347.5 mAh/g (vs. 221.5 mAh/g for the undoped electrode), and after 1000 cycles, the retention rate of the specific capacity is 74.9% as compared with only 42.7% for the undoped electrode. Even with higher loading amounts of 1.92 mg/cm2 Ni(OH)2, the specific capacity retention rate of the codoped electrode is still much higher than that of the undoped electrode. The high electrochemical performance can be attributed to the better ion/electron transfer ability of the codoped electrode. In conclusion, by the cathodic electrodeposition and in situ doping of CNTs/rGO, the porous structure and the conductive network in Ni(OH)2 film can be constructed, which can improve the ion/electron transfer ability, therefore, the high performance film electrode with higher loading amount of Ni(OH)2 can be prepared.