Ongoing technological advances in such disparate areas as consumer electronics, transportation, and energy generation and distribution are often hindered by the capabilities of current energy storage/conversion systems, thereby driving the search for high-performance power sources that are also economically viable, safe to operate, and have limited environmental impact. Electrochemical capacitors (ECs) are a class of energy-storage devices that fill the gap between the high specific energy of batteries and the high specific power of conventional electrostatic capacitors. The most widely available commercial EC, based on a symmetric configuration of two high-surface-area carbon electrodes and a nonaqueous electrolyte, delivers specific energies of up to ∼6 Whkg–1 with sub-second response times. Specific energy can be enhanced by moving to asymmetric configurations and selecting electrode materials (e.g., transition metal oxides) that store charge via rapid and reversible faradaic reactions. Asymmetric EC designs also circumvent the main limitation of aqueous electrolytes by extending their operating voltage window beyond the thermodynamic 1.2 V limit to operating voltages approaching ∼2 V, resulting in high-performance ECs that will satisfy the challenging power and energy demands of emerging technologies and in a more economically and environmentally friendly form than conventional symmetric ECs and batteries.

The swelling and exfoliation behaviors of layered potassium ruthenate and the resultant unilamellar crystallites of RuO2.10.2− with nanosheet morphology were studied. The reaction of layered H0.2RuO2.1·0.9H2O with tetrabutylammonium hydroxide (TBA+OH−) was found to be extremely sensitive to the interlayer water content. The use of highly hydrous layered protonic ruthenate was essential for obtaining direct exfoliation. The swelling behavior was also affected by the ratio of TBA+ to ion-exchangeable H+ in the layered compound. At low ratios of TBA+/H+≤1, the layered precursor scarcely exfoliated and mostly deposited as an intercalation compound. In the intermediate TBA+/H+ range, an auburn colloidal suspension containing exfoliated nanosheets was formed, while much larger ratios were less favorable for the exfoliation.

A titania-based self-standing film with high transparency and flexibility was successfully prepared via a sol-gel process, in which a titanium tetraisopropoxide/isostearate complex (precursor), n-hexylammonium isostearate (catalyst), and o-xylene (solvent) were used. The sol obtained by the sol-gel reaction was floated on a water surface to form an unsupported film. This film was composed of a titania/isostearate nanocomposite with ordered layer structure. The basal spacings of the nanocomposites depended on the chain length of the carboxylate modifier.

Nanoparticul ate Pt50Ru50 supported on a carbon black (CB) were prepared by an impregnation method and the effect of the nano and microstructure towards the electrocatalytic oxidation of methanol and carbon monoxide were evaluated. The in-house prepared PtRu nanoparticles were well-alloyed and finely dispersed on CB, as revealed by XRD and FESEM. FESTEM-EDX analysis of isolated PtRu single nanoparticles indicated that although the majority of the binary particles had a metal composition in accordance to the nominal ratio, some compositional deviation was observed. The activity towards electrocatalytic oxidation of methanol and preadsorbed carbon monoxide is discussed based on the nano and microstructure.

A protonated form of a layered perovskite was prepared from an Aurivillius phase Bi2SrNaNb3O12via acid treatments, and the effect of the type of mineral acids was investigated. The treatment with HX (X = Cl, Br, I) resulted in the formation of a protonated form H1.8[Sr0.8Bi0.2NaNb3O10], while no reactions were observed for HNO3 and H2SO4 under the present experimental conditions. All the products obtained by HX-treatments exhibited layered structures and the structures of the perovskite-like slabs were preserved.

Polycrystalline samples of Na1-xLnxNbO3 (Ln=La, Nd, Sm, Gd) were synthesized by solid-state reactions. Reduced niobates were obtained as single-phase perovskites for x=0.05 and 0.1 when Ln=La and Nd and x=0.05 when Ln=Sm. The Gd-substituted samples could not be prepared under the synthetic conditions studied. Compositional analysis of the products revealed a slight amount of sodium loss during synthesis. The structural parameters obtained from Rietveld analysis revealed an increase in unit-cell volume. All of the obtained samples showed semiconducting behavior. Similar semiconducting behavior was observed for the same x value, suggesting the weak influence of the different Ln species to the electrical properties.