▎ 摘　　要

To overcome the low electrical conductivity weakness of layered double hydroxide and to improve the electrochemical energy storage performance as supercapacitor electrodes, NiAl layered double hydroxide (NiAl-LDH) flowers with ultrathin structure grown on three-dimensional graphene (3DG) was constructed via a facile hydrothermal strategy. The NiAl-LDH/3DG composites as binder-free supercapacitor electrode showed a high specific capacitance of 884.5 F g(-1) at 1 A g(-1). Excellent cycle stability retaining 90 % of the initial capacitance after 7000 cycles at 5 A g(-1) was also demonstrated, with the coulombic efficiency stayed above 95 % during the whole cycling process. The excellent performances should be ascribed to the synergistic effect of NiAl-LDH and 3DG, in which the NiAl-LDH ultrathin nanoflake petals provide sufficient pseudocapacitive sites; while 3DG provides robust and highly interconnected skeleton for efficient mass/charge transport.