Li-air batteries have generated enormous interest as potential high specific energy alternatives to existing energy storage devices. However, Li-air batteries suffer from poor rechargeability caused by the instability of organic electrolytes and carbon cathodes. To understand and address this poor rechargeability, it is essential to elucidate the efficiency in which O2 is converted to Li2O2 (the desired discharge product) during discharge and the efficiency in which Li2O2 is oxidized back to O2 during charge. In this Letter, we combine many quantitative techniques, including a newly developed peroxide titration, to assign and quantify decomposition pathways occurring in cells employing a variety of solvents and cathodes. We find that Li2O2-induced electrolyte solvent and salt instabilities account for nearly all efficiency losses upon discharge, whereas both cathode and electrolyte instabilities are observed upon charge at high potentials.

Over the past 30 years the world market for semiconductors has grown at an average annual rate of approximately 15%. This growth has been maintained by the industry's unique ability to consistently provide over this time frame higher device performance at lower cost (achieving a 25-30% per-year cost reduction per function). Microlithography is the key technological driving force for this; in large part, the overall rate of progress in microelectronics is controlled by the rate of advances in microlithographic tools, methods, and materials. Today, the photolithographic technologies that have served the microelectronics community since its inception are widely viewed to be nearing their limits of extendibility. If the historical growth rate is to be maintained in the future, new imaging technologies with the capability of forming features with sub-100 nm dimensions must be devised and refined. In this paper we provide an overview of the issues to be considered for patterning in the sub-100 nm regime and describe the imaging technologies which are currently being evaluated for such use.

Artificial DNA nanostructures 1,2 show promise for the organization of functional materials 3,4 to create nanoelectronic 5 or nano-optical devices. DNA origami, in which a long single strand of DNA is folded into a shape using shorter 'staple strands' 6 , can display 6-nm-resolution patterns of binding sites, in principle allowing complex arrangements of carbon nanotubes, silicon nanowires, or quantum dots. However, DNA origami are synthesized in solution and uncontrolled deposition results in random arrangements; this makes it difficult to measure the properties of attached nanodevices or to integrate them with conventionally fabricated microcircuitry. Here we describe the use of electron-beam lithography and dry oxidative etching to create DNA origami-shaped binding sites on technologically useful materials, such as SiO 2 and diamond-like carbon. In buffer with 100 mM MgCl 2 , DNA origami bind with high selectivity and good orientation: 70-95% of sites have individual origami aligned with an angular dispersion (+ + + + +1 s.d.) as low as + + + + +108 8 8 8 8 (on diamond-like carbon) or + + + + +208 8 8 8 8 (on SiO 2 ).The semiconductor industry is currently faced with the challenges of developing lithographic technology for feature sizes below 22 nm (ref. 7) and exploring new classes of transistors that use carbon nanotubes 8 or silicon nanowires 9 . A major goal of nanotechnology is therefore to couple the self-assembly of molecular nanostructures with conventional microfabrication. A marriage of these so-called bottom-up and top-down fabrication methods would enable us to register individual molecular nanostructures, to electronically address them, and to integrate them into functional devices. One strategy is to use lithography to make templates onto which discrete components can self-assemble. Examples include the assembly of nanoparticles 10,11 , carbon nanotubes 12,13 and nanowires 14 . Lithographic templates can also be used to create hierarchical order: the nanostructures they organize can themselves have internal features with dimensions significantly smaller than those of the original template 15 and can serve as scaffolds for the assembly of still smaller components.Artificial DNA nanostructures are well suited to this approach. They can be synthesized with attachment groups (such as biotin or single-stranded DNA hooks) at defined locations, which can bind objects such as gold nanoparticles 4,16 . Easily designed in arbitrary shapes, DNA origami typically carry 200 such independently addressable sites at a resolution of 6 nm. Figure 1a depicts the self-assembly of triangular DNA origami in solution (see Supplementary Methods 1) and shows an atomic force micrograph (AFM) of their random deposition on mica, a technique ill-suited for integration with microfabrication. Previous lithographically patterned deposition of organic compounds 17 , single-and doublestranded DNA molecules [18][19][20] or DNA nanostructures 21 has achieved highly selective adsorption, but the molecules were smaller than the lith...

In this Letter, the effect of CO2 contamination on nonaqueous Li-O2 battery rechargeability is explored. Although CO2 contamination was found to increase the cell's discharge capacity, it also spontaneously reacts with Li2O2 (the primary discharge product of a nonaqueous Li-O2 battery) to form Li2CO3. CO2 evolution from Li2CO3 during battery charging was found to occur only at very high potentials (>4 V) compared to O2 evolution from Li2O2 (∼3-3.5 V), and as a result, the presence of CO2 during discharge dramatically reduced the voltaic efficiency of the discharge-charge cycle. These results emphasize the importance of not only completely removing CO2 from air fed to a Li-air battery, but also developing stable cathodes and electrolytes that will not decompose during battery operation to form carbonate deposits.

Acid diffusion during postexposure baking is viewed to be a limiting factor in the extension of lithography using chemically amplified resists to formation of nanoscale features. Quantification of thermally activated reaction-diffusion kinetics in these materials is therefore an important step in understanding the extendability of this class of resist systems. Previous investigations have addressed this issue, however there is poor agreement among them, and too few data exist in the literature to allow the systematics of the effect of polymer, photoacid generator, added base or other resist components on the diffusion process to be understood. We describe in this article a combined experimental and modeling protocol that is designed to elucidate the chemistry and physics of the reaction-diffusion process. Because it is physically based, not phenomenological, it provides a means of developing a set of predictive, mutually comparable data that will allow new insights to be developed into the nanoscale behavior of chemically amplified resist materials. We apply the protocol to a p-t-butyloxycarbonyloxystyrene/bis͑t-butylphenyl͒iodonium perfluorobutanesulfonate positive-tone photoresist system. The resulting kinetics measurements show that diffusion is environment sensistive and describable with two limiting diffusion coefficients. The Arrhenius parameters for the coefficients in p-t-butyloxycarbonyloxystyrene are D 0 ϭ1.9ϫ10 8 cm 2 /s and E a ϭ36.5 kcal/mol; those for diffusion in the deprotected polymer product p-hydroxystyrene are D 0 ϭ9ϫ10 Ϫ3 cm 2 /s and E a ϭ22.1 kcal/mol. The coefficients are much smaller than previously reported, resulting in a very slow diffusion rate. The model indicates that the considerable image spreading observed during the postexposure bake process is attributable primarily to the efficiency of the catalytic chemistry. Our results suggest that numerical models currently used for prediction of imaging in chemically amplified resists may require refinement in order to be useful for feature sizes below 100 nm and for new classes of resist systems.