Self-Standing Flexible N-Doped Graphene/CNTs Supported Spiral Low-Crystalline Ni(OH)2 Electrode with Ultra-Long Cycling Stability for Supercapacitors

Carbon materials are widely used as anodes of supercapacitors due to the long cycling stability, but the low capacitance results in low energy density of the supercapacitor device in aqueous solution, greatly limiting the application field of the supercapacitor. Here, the spiral low-crystalline Ni(OH) 2 supported on self-standing layered film structure of N-doped graphene/carbon nanotubes film (NCF) is reported. The prepared flexible film electrode of low-crystalline Ni(OH) 2 /NCF is functioned as cathode directly, presenting high gravimetric capacitance (GC) and areal capacitance of 2130[Formula: see text]F[Formula: see text]g[Formula: see text] (2[Formula: see text]A[Formula: see text]g[Formula: see text]) and 2.88[Formula: see text]F[Formula: see text]cm[Formula: see text] (1[Formula: see text]A[Formula: see text]g[Formula: see text]). Also, this self-standing electrode film shows ultra-long cycle life, retaining 111.4% of initial capacitance after 30 000 circles at large current densities (20[Formula: see text]A[Formula: see text]g[Formula: see text]) and almost 0% fade before 10 000 circles. Moreover, Ni(OH) 2 /NCF and activated polyaniline derived carbon (APDC) have been assembled into an asymmetric supercapacitor, exhibiting a high gravimetric energy density of 60[Formula: see text]Wh[Formula: see text]kg[Formula: see text] at 800[Formula: see text]W[Formula: see text]kg[Formula: see text], suggesting that the obtained electrode has a good prospect application in long cycling stability with high energy density of supercapacitor devices.