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A two-dimensional (2D) nanoporous Ni(OH) 2 film was successfully developed from triethanolamine (TEA) as the alkali source and soft template using a scalable hydrothermal technique. The nanostructured Ni(OH) 2 film was flexible and translucent, and could be directly compressed on a current collector. Owing to the uniform well-defined morphology and stable structure, the Ni(OH) 2 film binder-free electrode displayed a high specific capacity, exceptional rate capability, and admirable cycle life. The specific capacitance was 453.6 mA h g -1 (1633 F g -1 ) at 0.5 A g -1 . The assembled Ni(OH) 2 //activated carbon (AC) asymmetric supercapacitor (ASC) device had an energy density of 58.7 W h kg -1 at a power density of 400 W kg -1 . These prominent electrochemical properties of Ni(OH) 2 were attributed to the high electrical conductivity, high surface area, and unique porous architecture. Free tailoring, binder-free, and direct pressing were the most significant achievements of the Ni(OH) 2 film in the development of high-performance energy storage devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

This study proposes a facile solvothermal synthesis of nickel tungstate (NiWO 4 ) nanowires for application as a novel cathode material for supercapacitors. The structure, morphology, surface area and pore distribution were characterized and their capacitive performances were investigated. The results showed that the NiWO 4 nanowires synthesized in ethylene glycol solvent could offer a high specific capacitance of 1190 F g -1 at a current density of 0.5 A g -1 and a capacitance retaining ratio of 61.5% within 0.5-10 A g -1 . When used as a cathodic electrode of an asymmetric supercapacitor (ASC), the NiWO 4 nanowire based device can be cycled reversibly in a high-voltage region of 0-1.7 V with a high specific capacitance of 160 F g -1 at 0.5 A g -1 , which therefore contributed to an energy density of 64.2 W h kg -1 at a power density of 425 W kg -1 . Moreover, 92.8% of its initial specific capacitance can be maintained after 5000 consecutive cycles (5 A g -1 ). These excellent capacitive properties make NiWO 4 a credible electrode material for high-performance supercapacitors., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)