Naveed Hussain

Cycling of a Lithium‐Ion Battery with a Silicon Anode Drives Large Mechanical Actuation

Lithium-ion batteries with a Si anode can drive large mechanical actuation by utilizing the dramatic volume changes of the electrode during the charge/discharge cycles. A large loading of more than 10 MPa can be actuated by a LiFePO4 ||Si full battery with a rapid response while the driving voltage is lower than 4 V.

Ultrathin Bi Nanosheets with Superior Photoluminescence

Despite substantial progress in the science and technology of 2D nanomaterials, facile fabrication of ultrathin 2D metals remains challenging. Herein, an efficient hot-pressing method is developed to fabricate free-standing ultrathin Bi nanosheets from Bi nanoparticles. Highly crystalline Bi nanosheets with thickness as low as ≈2 nm and area of more than several micrometers are successfully fabricated on silicon substrates. The ultrathin Bi nanosheets exhibit morphology and structural dependent enhanced broad range photoemission in visible region of spectrum. Our cost-effective hot-pressing strategy may open an insight for production, application, and deficient fundamental understanding of other 2D semimetals/metalloids and noble metals.

Effect of Annealing Atmosphere Induced Crystallite Size Changes on the Electrochemical Properties of TiO2 Nanotubes Arrays

TNAs (Titanium dioxide nanotube arrays) were synthesized by electrochemical anodization and these TNAs were annealed in different gas atmosphere such as argon, air, hydrogen and nitrogen. This annealing in different atmosphere brought variation in crystallite size (27 ~ 33 nm), which influences on electrochemical properties. The specific capacity of Ar, Air, N2 and H2-annealed TNAs was around ~165, 185, 177 and 190 mAh g, respectively. The crystallite size of anatase TNAs seemed to be responsible for the change in lithium storage capacity, indicating that structural changes of TNAs were playing major role in electrochemical properties.

Ice Melting to Release Reactants in Solution Syntheses

Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO3 was frozen and dropped into a reductive NaBH4 solution at about 0 °C. The ultra-slow release of reactants was successfully achieved. An ice-melting process can be used to synthesize atomically dispersed metals, including cobalt, nickel, copper, rhodium, ruthenium, palladium, silver, osmium, iridium, platinum, and gold, which can be easily extended to other solution syntheses (such as precipitation, hydrolysis, and displacement reactions) and provide a generalized method to redesign the interphase reaction kinetics and ion diffusion in wet chemistry.

Large-area, transferable sub-10 nm polymer membranes at the air–water interface

Large-area, pinhole-free, and ultrathin polymer membranes with thicknesses of only a few nanometers have attracted increasing attention for their applications in molecular separation, flexible optoelectronics, and sensors. They can potentially be developed for surface protection as well. In this study, we report an effective way to obtain large-scale polymer coatings with a thickness down to 10 nm, which effectively protects metals from corrosion. We develop a facile and scalable method to fabricate freestanding polymer membranes with thickness below 10 nm by dropping the precursor polymer solution on a water surface. By optimizing the surface tension of the polymer solution, the solution could spontaneously spread on the water surface to form a continuous and uniform solid membrane, collected as a freestanding thin membrane. The obtained polymer membranes could then easily be transferred on a metal substrate as highly flexible and stable anti-corrosion coatings. Electrochemical measurements performed in a 0.1 M Na2SO4 solution demonstrated the excellent anti-corrosion properties of the sub-10 nm polymer membranes whose corrosion rate was less than 1% of the corrosion rate of the bare metal. We also demonstrate that the polymer membrane exhibits high performance as a protection layer for flexible circuits.