We report a novel three-dimentional (3D) porous nano-Ni/Co(OH)2 nanoflake composite film electrode for potential supercapacitor applications with both high power and energy capabilities. The 3D porous nano-Ni film with highly porous nanoramified walls functions as a scaffold to anchor Co(OH)2 nanoflakes to produce a 3D nanoporous metal/hydroxide nanoflake composite electrode. Co(OH)2 nanoflakes with thicknesses of 20 nm are directly electrodeposited on highly conductive 3D porous nano-Ni film prepared via a hydrogen bubble template. Impressively, the Co(OH)2 nanoflake in the composite film exhibits a high specific capacitance of 1920 F g–1 at 40 A g–1, with a corresponding energy density as high as 80 W h kg–1 at a power density of 11 kW kg–1. Moreover, the designed composite film exhibits excellent cycling stability, making it one of the best electrode materials for high-performance supercapacitors. This work demonstrates that the 3D porous nanometal/hydroxide nanoflake composite approach is an effective strategy toward supercapacitors with high energy and power densities.

Hierarchical, nanostructured nickel phosphide (h-Ni2P) spheres are synthesized by a one-pot reaction from an organic-phase mixture of nickel acetylacetonate, trioctylphosphine, tri-n-octylamine, and oleylamine (OAm). OAm is used as a surfactant to modify the surface morphology of Ni2P spheres. The h-Ni2P spheres are composed of ordered nanoparticles with 5–10 nm sizes and filled by amorphous carbon. The hierarchical structure can greatly increase the contact area between Ni2P and electrolyte, which provides more sites for Li+ accommodation, shortens the diffusion length of Li+, and enhances the reactivity of the electrode reaction. Also, the amorphous carbon and the hierarchical Ni2P nanostructures can buffer volume expansion and thus increase the electrode stability during cycling. In the context of storage behavior, the h-Ni2P electrode exhibits high capacity as well as Coulombic efficiency. After 50 cycles, the reversible capacity of h-Ni2P spheres is 365.3 mA h g–1 at 0.5 C and 257.8 mA h g–1 at 1 C, much higher than that of Ni2P spheres (97.2 mA h g–1 at 0.5 C). At a high rate of 3 C, the specific capacity of h-Ni2P is still as high as 167.1 mA h g–1.

Iron disulfide (FeS 2 ) powders were successfully synthesized by hydrothermal method. Cetyltrimethylammonium bromide (CTAB) had a great influence on the morphology, particle size, and electrochemical performance of the FeS 2 powders. The as-synthesized FeS 2 particles with CTAB had diameters of 2-4 lm and showed a sphere-like structure with sawtooth, while the counterpart prepared without CTAB exhibited irregular morphology with diameters in the range of 0.1-0.4 lm. As anode materials for Li-ion batteries, their electrochemical performances were investigated by galvanostatic charge-discharge test and electrochemical impedance spectrum. The FeS 2 powder synthesized with CTAB can sustain 459 and 413 mAh g -1 at 89 and 445 mA g -1 after 35 cycles, respectively, much higher than those prepared without CTAB (411 and 316 mAh g -1 ). The enhanced rate capability and cycling stability were attributed to the less-hindered surface layer and better electrical contact from the sawtooth-like surface and micro-sized sphere morphology, which led to enhanced process kinetics.

A new synthetic route to ~4 nm grain-sized SnO 2 was proposed which involved a homogeneous precipitation in a deep eutectic solvent (DES) at room temperature. The white SnO 2 precipitate was obtained from SnCl 2 ⋅ 2 H 2 O dissolved DES by injecting slow drop-wise H 4 N 2 ⋅ H 2 O under stirring. The as-prepared nanocrystalline SnO 2 has a Brunauer–Emmett–Teller surface area of 65.12m2/g with an average Barretl–Joyner–Halenda pore diameter of 3.5 nm. As anode for lithium ion batteries, the nanocrystalline SnO 2 electrode delivered an initial charge capacity as high as 1045 mAh/g and its capacity retention is 58% after 30 cycles.

teries. -The title cathode material is prepared by freeze-drying of an aqueous solution containing NH4VO3, LiOH, and H3PO4 (-53°C, 48 h) followed by calcination of the obtained precursor together with polystyrene spheres as the carbon source (Ar flow, 750°C, 8 h). Li3V2(PO4)3/C shows high rate capability and excellent cycling stability, making it an attractive high-power cathode for lithium ion batteries. -(QIAO, Y. Q.; WANG*, X. L.; MAI, Y. J.; XIA, X. H.; ZHANG, J.; GU, C. D.; TU, J. P.; J. Alloys Compd. 536 (2012) 132-137, http://dx.