Hybrid Porous Microparticles Based on a Single Organosilica Cyclophosphazene Precursor.

Porous organosilica microparticles consisting of silane-derived cyclophosphazene bridges were synthesized by a surfactant-mediated sol-gel process. Starting from the substitution of hexachlorocyclotriphosphazene with allylamine, two different precursors were obtained by anchoring three or six alkoxysilane units, via a thiol-ene photoaddition reaction. In both cases, spherical, microparticles (size average of ca. 1000 nm) with large pores were obtained, confirmed by both, scanning and transmission electron microscopy. Particles synthesized using the partially functionalized precursor containing free vinyl groups were further functionalized with a thiol-containing molecule. While most other reported mesoporous organosilica particles are essentially hybrids with tetraethyl orthosilicate (TEOS), a unique feature of these particles is that structural control is achieved by exclusively using organosilane precursors. This allows an increase in the proportion of the co-components and could springboard these novel phosphorus-containing organosilica microparticles for different areas of technology.

Enhancing cycling durability of Li-ion batteries with hierarchical structured silicon-graphene hybrid anodes.

Hybrid anode materials consisting of micro-sized silicon (Si) particles interconnected with few-layer graphene (FLG) nanoplatelets and sodium-neutralized poly(acrylic acid) as a binder were evaluated for Li-ion batteries. The hybrid film has demonstrated a reversible discharge capacity of ∼1800 mA h g-1 with a capacity retention of 97% after 200 cycles. The superior electrochemical properties of the hybrid anodes are attributed to a durable, hierarchical conductive network formed between Si particles and the multi-scale carbon additives, with enhanced cohesion by the functional polymer binder. Furthermore, improved solid electrolyte interphase (SEI) stability is achieved from the electrolyte additives, due to the formation of a kinetically stable film on the surface of the Si.

Heteroatom Doped-Carbon Nanospheres as Anodes in Lithium Ion Batteries.

Long cycle performance is a crucial requirement in energy storage devices. New formulations and/or improvement of "conventional" materials have been investigated in order to achieve this target. Here we explore the performance of a novel type of carbon nanospheres (CNSs) with three heteroatom co-doped (nitrogen, phosphorous and sulfur) and high specific surface area as anode materials for lithium ion batteries. The CNSs were obtained from carbonization of highly-crosslinked organo (phosphazene) nanospheres (OPZs) of 300 nm diameter. The OPZs were synthesized via a single and facile step of polycondensation reaction between hexachlorocyclotriphosphazene (HCCP) and 4,4'-sulphonyldiphenol (BPS). The X-ray Photoelectron Spectroscopy (XPS) analysis showed a high heteroatom-doping content in the structure of CNSs while the textural evaluation from the N2 sorption isotherms revealed the presence of micro- and mesopores and a high specific surface area of 875 m²/g. The CNSs anode showed remarkable stability and coulombic efficiency in a long charge-discharge cycling up to 1000 cycles at 1C rate, delivering about 130 mA·h·g-1. This study represents a step toward smart engineering of inexpensive materials with practical applications for energy devices.

Encapsulation and release of corrosion inhibitors into titania nanocontainers.

Titania nanocontainers were synthesized through a two-step process and then loaded with 8-hydroxyquinoline (8-HQ) and p-toluenesulfonic acid (p-TSA). The size of the containers was 242 +/- 10 nm as determined by Scanning Electron Microscopy (SEM). X-Ray Diffraction Analysis (XRD) showed that the titania nanocontainers consist of anatase and rutile crystalline phases. The presence of 8-HQ and p-TSA in the nanocontainers was confirmed with Fourier Transform Infrared Spectroscopy (FT-IR). The loading of the inhibitors in the nanocontainers was estimated with Thermo Gravimetric Analysis (TGA). The loading amount of 8-HQ is 3.56% w/w and that of p-TSA is 6.13%. Based on the size of the nanocontainers and the assumption that they are not broken, the amount of approximately with 2.83 x 10(6) molecules of 8-HQ and 3.86 x 10(6) molecules of p-TSA per nanocontainer was estimated. Furthermore, release studies of 8-HQ and p-TSA in a corrosive environment were studied by potentiodynamic measurements showing that the inhibitors are released from the nanocontainers, suppressing the corrosion activities. SEM and Dynamic Light Scattering (DLS) measurements confirmed that the nanocontainers are not agglomerated and keep their shape after suspension in 0.5 M NaCI solution for more than 72 hours.