Fabrication of Porous Carbon/TiO₂ Composites through Polymerization-Induced Phase Separation and Use As an Anode for Na-Ion Batteries

Polymerization-induced phase separation of nanoparticle-filled solution is demonstrated as a simple approach to control the structure of porous composites. These composites are subsequently demonstrated as the active component for sodium ion battery anode. To synthesize the composites, we dissolved/dispersed titanium oxide (anatase) nanoparticles (for sodium insertion) and poly­(hydroxybutyl methacrylate) (PHBMA, porogen) in furfuryl alcohol (carbon precursor) containing a photoacid generator (PAG). UV exposure converts the PAG to a strong acid that catalyzes the furfuryl alcohol polymerization. This polymerization simultaneously decreases the miscibility of the PHBMA and reduces the mobility in the mixture to kinetically trap the phase separation. Carbonization of this polymer composite yields a porous nanocomposite. This nanocomposite exhibits nearly 3-fold greater gravimetric capacity in Na-ion batteries than the same titanium oxide nanoparticles that have been coated with carbon. This improved performance is attributed to the morphology as the carbon content in the composite is five times that of the coated nanoparticles. The porous composite materials exhibit stable cyclic performance. Moreover, the battery performance using materials from this polymerization-induced phase separation method is reproducible (capacity within 10% batch-to-batch). This simple fabrication methodology may be extendable to other systems and provides a facile route to generate reproducible hierarchical porous morphology that can be beneficial in energy storage applications

Syndiotactic Polystyrene-Based Ionogel Membranes for High Temperature Electrochemical Applications

This work focuses on ionogel membranes for use in Li-ion batteries fabricated from syndiotactic polystyrene (sPS) gels filled with ionic liquids (ILs). The aim is to increase the operating temperature of Li-ion batteries. Thermal stability and safe operation of Li-ion batteries are two key attributes for their success in hybrid vehicles and other high-temperature applications. The volatility of the liquid electrolytes in current lithium-ion battery technology causes thermal runaway leading to fire, explosion, and swelling of the cell. The approach followed in this work combines the thermal stability and ruggedness of sPS and the extremely low volatility of ILs. The performances of lithium metal/graphite half-cells fabricated with ionogel membranes and those with Celgard-3501 membranes are evaluated at both room temperature and at elevated temperatures of 100 °C. Our data show that the cells with ionogel membranes can be operated continuously at 100 °C without failure. In addition, better charge–discharge capacity is obtained due to high ionic conductivity and high electrolyte retention both derived from high porosity of sPS gels and better wetting of sPS by the ILs

Three-Dimensional Bicontinuous Graphene Monolith from Polymer Templates

The two-dimensional single-layer and few-layered graphene exhibit many attractive properties such as large specific surface area and high charge carrier mobility. However, graphene sheets tend to stack together and form aggregates, which do not possess the desirable properties associated with graphene. Herein, we report a method to fabricate three-dimensional (3D), bicontinuous graphene monolith through a versatile hollow nickel (Ni) template derived from polymer blends. The poly(styrene)/poly(ethylene oxide) were used to fabricate a bicontinuous gyroid template using controlled phase separation. The Ni template was formed by electroless metal depositing on the polymer followed by removing the polymer phase. The resulting hollow Ni structure was highly porous (95.2%). Graphene was then synthesized from this hollow Ni template using chemical vapor deposition and the free-standing bicontinuous graphene monolith was obtained in high-throughput process. Finally, the bicontinuous graphene monolith was used directly as binder-free electrode in supercapacitor applications. The supercapacitor devices exhibited excellent stability

Comparison of energy, total choline, individual choline-containing compounds and betaine between colorectal cancer cases and controls.

<p>^a Intakes of total choline, individual choline-containing compounds and betaine were adjusted for the daily energy intake using the residual method.</p><p>Wilcoxon rank-sum test comparing the median consumption levels between cases and controls.</p><p>Comparison of energy, total choline, individual choline-containing compounds and betaine between colorectal cancer cases and controls.</p

Odds ratios (ORs) and 95% confidence intervals (95%CIs) of colorectal cancer according to quartiles of choline and betaine intake.

<p>^a Odds ratio was adjusted for age (continuous), sex (men/women), residence (urban/rural), marital status (married/other), education (primary school or blow/secondary school/high school/college or above), income level (<2,000/2,001–5,000/5,001–8,000/>8,001), occupation (white collar worker/blue collar worker/farmer or other), family history of cancer (yes/no), smoking status (current/never or past), passive smoking (yes/no), alcohol drinking (yes/no), degree of physical activity (less active/moderate active/more active), BMI (continuous).</p><p>^b Odds ratio was adjusted for the various above confounders and red meat (continuous), fish (continuous).</p><p>^c Odds ratio was adjusted for the various above confounders and red meat (continuous), fish (continuous), beans (continuous).</p><p>^d Odds ratio was adjusted for the various above confounders in ^b and folate intake (continuous).</p><p>^e Odds ratio was adjusted for the various above confounders in ^c and folate intake (continuous).</p><p>Odds ratios (ORs) and 95% confidence intervals (95%CIs) of colorectal cancer according to quartiles of choline and betaine intake.</p

Hierarchical Electrospun and Cooperatively Assembled Nanoporous Ni/NiO/MnO_<i>x</i>/Carbon Nanofiber Composites for Lithium Ion Battery Anodes

A facile method to fabricate hierarchically structured fiber composites is described based on the electrospinning of a dope containing nickel and manganese nitrate salts, citric acid, phenolic resin, and an amphiphilic block copolymer. Carbonization of these fiber mats at 800 °C generates metallic Ni-encapsulated NiO/MnO_<i>x</i>/carbon composite fibers with average BET surface area (150 m²/g) almost 3 times higher than those reported for nonporous metal oxide nanofibers. The average diameter (∼900 nm) of these fiber composites is nearly invariant of chemical composition and can be easily tuned by the dope concentration and electrospinning conditions. The metallic Ni nanoparticle encapsulation of NiO/MnO_<i>x</i>/C fibers leads to enhanced electrical conductivity of the fibers, while the block copolymers template an internal nanoporous morphology and the carbon in these composite fibers helps to accommodate volumetric changes during charging. These attributes can lead to lithium ion battery anodes with decent rate performance and long-term cycle stability, but performance strongly depends on the composition of the composite fibers. The composite fibers produced from a dope where the metal nitrate is 66% Ni generates the anode that exhibits the highest reversible specific capacity at high rate for any composition, even when including the mass of the nonactive carbon and Ni⁰ in the calculation of the capacity. On the basis of the active oxides alone, near-theoretical capacity and excellent cycling stability are achieved for this composition. These cooperatively assembled hierarchical composites provide a platform for fundamentally assessing compositional dependencies for electrochemical performance. Moreover, this electrospinning strategy is readily scalable for the fabrication of a wide variety of nanoporous transition metal oxide fibers

Correlation coefficients between energy-adjusted folate, betaine, choline and individual choline-containing compounds in controls (two-tailed Spearman).

<p>** Correlations are significant (<i>p</i><0.01).</p><p>* Correlations are significant (<i>p</i><0.05)</p><p>Correlation coefficients between energy-adjusted folate, betaine, choline and individual choline-containing compounds in controls (two-tailed Spearman).</p

Odds ratios (ORs) and 95% confidence intervals (95%CIs) of colorectal cancer according to quartiles of five main choline-containing compounds intakes.

<p>^a Odds ratio was adjusted for age (continuous), sex (men/women), residence (urban/rural), marital status (married/other), education (primary school or blow/secondary school/high school/college or above), income level (<2,000/2,001–5,000/5,001–8,000/>8,001), occupation (white collar worker/blue collar worker/farmer or other), family history of cancer (yes/no), smoking status (current/never or past), passive smoking (yes/no), alcohol drinking (yes/no), degree of physical activity (less active/moderate active/more active), and BMI (continuous).</p><p>^b Odds ratio was adjusted for the various above confounders and folate intake (continuous).</p><p>Odds ratios (ORs) and 95% confidence intervals (95%CIs) of colorectal cancer according to quartiles of five main choline-containing compounds intakes.</p

Top five food sources of total choline, choline-containing compounds, and betaine among control subjects.

<p>Top five food sources of total choline, choline-containing compounds, and betaine among control subjects.</p

Demographics, lifestyle characteristics, and select hip fracture risk factors of study population in Guangzhou, China.

<p>Continuous variables were described by means ±standard deviation.</p>a<p>Occupation: “mental work” refers to those works which need less physical activity, such as administrators, managers, clerks, professionals or other white collars.</p>b<p>House orientations: ‘head’ referred to the orientation of the living room. Housing with east, south, southeast, southwest, northeast, and northwest orientations designated a head in the sun and other orientations designated a head in the shade.</p>c<p>Smoking was defined as having smoked ≥1 cigarette daily for at least six consecutive months.</p>d<p>Passive smoking was defined as being exposed to other's tobacco smoking for ≥5 minutes daily in the previous five years.</p>e<p>Alcohol drinkers were defined as having had wine ≥1 time(s) daily for at least six consecutive months.</p>f<p>Tea drinkers were defined as drinking at least one cup of tea per week in the previous six months.</p>g<p>Physical activities included daily occupational, leisure-time, and household-chores, evaluated by metabolic equivalent (MET) hours per day.</p