Uniform ZnO QDs with controllable sizes from 2 to 7 nm on graphene were synthesized. The ZnO QD/graphene nanocomposites show enhanced electrochemical properties as lithium ion battery anodes.

Amorphous TiO 2 (a-TiO 2 ) thin films were conformally coated onto the surface of hydroxyl functionalized multi-walled carbon nanotubes (CNTs) using atomic layer deposition (ALD). The electrochemical characteristics of the a-TiO 2 /CNT nanocomposites were then determined using cyclic voltammetry and galvanostatic charge/discharge curves. The ultrathin TiO 2 ALD films displayed high specific capacity and high rate capability. The specific capacities of the a-TiO 2 /CNT nanocomposites after 50 and 100 TiO 2 ALD cycles at 100 mA/g were 220 mAh/g and 240 mAh/g, respectively. For CNTs coated with 100 TiO 2 ALD cycles, 88% of the capacity at 100 mA/g could be maintained at 1 A/g. When the voltage window for the a-TiO 2 /CNT nanocomposites was extended down to 0.5 V versus Li/Li + , the CNTs coated with 50 and 100 TiO 2 ALD cycles exhibited specific capacities at 100 mA/g of 275 mAh/g and 312 mAh/g, respectively. These high capacities are higher than the bulk theoretical values and are attributed to additional interfacial charge storage resulting from the high surface area of the a-TiO 2 /CNT nanocomposites. Free-standing TiO 2 -CNT electrodes were also fabricated and displayed excellent capacity and rate capability. These results demonstrate that TiO 2 ALD on high surface area CNT substrates can provide high power and high capacity anodes for lithium ion batteries.

Uniform amorphous vanadium oxide films were coated on graphene via atomic layer deposition and the nano-composite displays an exceptional capacity of ~900 mA h g(-1) at 200 mAg(-1) with an excellent capacity retention at 1 A g(-1) after 200 cycles. The capacity contribution (1161 mA h g(-1)) from vanadium oxide only almost reaches its theoretical value.

Amorphous SnO2 (a-SnO2) thin films were conformally coated onto the surface of reduced graphene oxide (G) using atomic layer deposition (ALD). The electrochemical characteristics of the a-SnO2/G nanocomposites were then determined using cyclic voltammetry and galvanostatic charge/discharge curves. Because the SnO2 ALD films were ultrathin and amorphous, the impact of the large volume expansion of SnO2 upon cycling was greatly reduced. With as few as five formation cycles best reported in the literature, a-SnO2/G nanocomposites reached stable capacities of 800 mAh g(-1) at 100 mA g(-1) and 450 mAh g(-1) at 1000 mA g(-1). The capacity from a-SnO2 is higher than the bulk theoretical values. The extra capacity is attributed to additional interfacial charge storage resulting from the high surface area of the a-SnO2/G nanocomposites. These results demonstrate that metal oxide ALD on high surface area conducting carbon substrates can be used to fabricate high power and high capacity electrode materials for lithium-ion batteries.

We present results on patterning microstructures using laser-guidance deposition of nanoparticles from particle-in-solvent suspensions. A laser beam axially confines and propels the particles inside a hollow optical fiber towards a substrate. Confining is provided by the gradient forces arising from light refraction or electrical forces on polarizable particles. The driving force results from the momentum conservation of photons scattered on particles. Polystyrene particles (100 and 400 nm in diameter) and gold particles (from 8 to 50 nm) with different surface organic functionality serve as a constructive material for fabrication of microstrips. In the experiments, the laser power varies from 0.1 to 1.6 W. The microstrips produced under different deposition conditions are studied using optical microscopy and atomic force microscopy. It was found that deposited polystyrene and gold particles form nanoclusters consisting of at least several particles. If deposited at an appropriate rate, such nanoclusters form multilayer microstrips of high particle density. The typical width of the microstrips ranges from less than 10 microns to 100 microns. This technique allows us to fabricate parallel arrays made of colloidal particles with different surface functionality, which seems to be an especially attractive approach for developing novel chemical and biological microsensors.