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In this study, carbon nanorods (CNR) and graphene nanoribbons (GNR) derived from metal-organic frameworks (MOFs) were first prepared by solvothermal method. Then, Ni-Co layered double hydroxide (LDH)/CNR and LDH/GNR composite materials for supercapacitors were synthesized using a facile co-precipitation method. With the help of GNR, the Ni-Co LDH/GNR composite material showed great specific capacity (1765 F g-1), rate performance (68% capacity retention when current density increased from 1 to 20 A g-1) and cycling stability (83% capacity retention after 2000 charge-discharge cycles at 5 A g-1). Furthermore, an asymmetric supercapacitor (ASC) with Ni-Co LDH/GNR as positive and activated carbon (AC) as negative electrodes was fabricated. The ASC device delivered a high energy density of 25.4 W h kg-1 at power density of 749 W kg-1 and exhibited excellent cycling stability (96% specific capacity retention after 5000 cycles).

(1Àx)(K 0.48 Na 0.52 )(Nb 0.95 Ta 0.05 )O 3 -xLiSbO 3 [(1Àx)KNNTÀ xLS] lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was identified in the composition range of 0.03oxo0.05. The ceramics near the MPB exhibit a strong compositional dependence and enhanced electrical properties. The (1Àx)KNNTxLS (x 5 0.04) ceramics exhibit good electrical properties (d 33 5 250 pC/N, k p 5 45.1%, k t 5 46.3%, T c 5 3481C, T oÀt 5 741C, P r 5 25.9 lC/cm 2 , E c 5 10.7 kV/cm, e r B1352, tan dB3%). These results show that (1Àx)KNNT-xLS ceramic is a promising lead-free piezoelectric material.

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