An important trend in electronics involves the development of materials, mechanical designs and manufacturing strategies that enable the use of unconventional substrates, such as polymer films, metal foils, paper sheets or rubber slabs. The last possibility is particularly challenging because the systems must accommodate not only bending but also stretching. Although several approaches are available for the electronics, a persistent difficulty is in power supplies that have similar mechanical properties, to allow their co-integration with the electronics. Here we introduce a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual 'self-similar' interconnect structures between them. The result enables reversible levels of stretchability up to 300%, while maintaining capacity densities of B1.1 mAh cm À 2 . Stretchable wireless power transmission systems provide the means to charge these types of batteries, without direct physical contact.

Atomic-scale control and manipulation of the microstructure of polycrystalline thin films during kinetically limited low-temperature deposition, crucial for a broad range of industrial applications, has been a leading goal of materials science during the past decades. Here, we review the present understanding of film growth processes—nucleation, coalescence, competitive grain growth, and recrystallization—and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.

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Structural and electronic investigations were conducted on lithium nickel oxide-based particles used in positive electrodes of 18650-type high-power Li-ion cells. K-edge X-ray absorption spectroscopy ͑XAS͒ revealed trivalent Ni and Co ions in the bulk LiNi 0.8 Co 0.2 O 2 powder used to prepare the high power electrode laminates. Using oxygen K-edge XAS, high resolution electron microscopy, nanoprobe diffraction, and electron energy-loss spectroscopy, we identified a Ͻ5 nm thick modified layer on the surface of the oxide particles, which results from the loss of Ni and Li ordering in the layered R3 m structure. This structural change was accompanied by oxygen loss and a lowering of the Ni-and Co-oxidation states in the surface layer. Growth of this surface layer may contribute to the impedance rise observed during accelerated aging of these Li-ion cells.The Li x Ni 1Ϫx O solid solutions form over a lithium concentration range of 0 р x р 0.5. 1-3 When lithium is added to NiO (x ϭ 0), conventional wisdom states that the Li ϩ charge compensation is achieved through the creation of Ni ϩ3 ions. The crystal structure of these solid solutions changes with x. For low x (0 р x р 0.3), lithium cations substitute randomly for nickel cations in the NiO lattice ͑NaCl-type structure͒. For x Ͼ 0.3, ordering of the Li and Ni ions starts in alternating cubic ͑111͒ planes culminating at x ϭ 0.5 in layered LiNiO 2 (␣-NaFeO 2 structure͒. The oxidation state of Ni has long been believed to be ϩ3 in LiNiO 2 -based compounds.Recent electronic structure investigations have, however, sparked a debate on the Ni oxidation states. Several spectroscopic and theoretical studies have concluded that hole states in Li x Ni 1Ϫx O compounds are localized predominantly at oxygen rather than at nickel, and that the charge compensating states are better described as O Ϫ rather than Ni ϩ3 ; that is, the nickel ions retain their ϩ2 character for all values of x. [4][5][6][7][8] In contrast, other researchers have affirmed the traditional view that Ni ϩ3 is present in LiNiO 2 -based compounds. 9-13 The charge-compensation debate achieves additional complexity when lithium is intercalated and deintercalated from these compounds. Several theoretical and ex situ experimental studies have indicated that the majority of the electron charge is accommodated by the oxygen anions during Li-ion cell cycling, [14][15][16][17][18][19] whereas other in situ experimental studies have indicated that the charge compensation occurs predominantly at the nickel sites. [11][12][13] An understanding of nickel oxidation states and electron charge compensation processes is critical for determining mechanisms that limit the calendar life and thermal abuse characteristics of high power Li-ion cells being developed for hybrid electric vehicle ͑HEV͒ applications as part of the Advanced Technology Development program in the United States. [20][21][22][23][24][25] In this program, the capacity and pulse power capabilities of ϳ1 Ah capacity, 18650-type ͑18 mm diam, 65 mm long͒ cells,...

Highly sensitive, mechanically robust Al2O3 nanopores are fabricated and characterized. These sensors allow for size control with sub‐nanometer precision, chemical modification, and exhibit superior noise performance and increased lifetime over their solid‐state counterparts. This new class of nanopore sensor is used in dsDNA studies and finds broad application in bio‐nanotechnology.

The ability of electron microscopes to analyze all the atoms in individual nanostructures is limited by lens aberrations. However, recent advances in aberration-correcting electron optics have led to greatly enhanced instrument performance and new techniques of electron microscopy. The development of an ultrastable electron microscope with aberration-correcting optics and a monochromated high-brightness source has significantly improved instrument resolution and contrast. In the present work, we report information transfer beyond 50 pm and show images of single gold atoms with a signal-to-noise ratio as large as 10. The instrument's new capabilities were exploited to detect a buried Sigma3 {112} grain boundary and observe the dynamic arrangements of single atoms and atom pairs with sub-angstrom resolution. These results mark an important step toward meeting the challenge of determining the three-dimensional atomic-scale structure of nanomaterials.

Density functional methods were used to calculate binding and diffusion energies of adatoms, molecules, and small clusters on TiN͑001͒ and TiN͑111͒ surfaces in order to isolate the key atomistic processes which determine texture evolution during growth of polycrystalline TiN layers. The surface energy for nonpolar TiN͑001͒, 81 meV/Å 2 , was found to be lower than that of both Nand Ti-terminated TiN͑111͒ polar surfaces, 85 and 346 meV/Å 2. While N 2 molecules are only weakly physisorbed, Ti adatoms form strong bonds with both TiN͑001͒, 3.30 eV, and TiN͑111͒, 10.09 eV. Ti adatom diffusion is fast on ͑001͒, but slow on ͑111͒ surfaces, with calculated energy barriers of 0.35 and 1.74 eV, respectively. The overall results show that growth of 111-oriented grains is favored under conditions typical for reactive sputter deposition. However, the presence of excess atomic N ͑due, for example, to collisionally induced dissociation of energetic N 2 ϩ ions͒ leads to a reduced Ti diffusion length, an enhanced surface island nucleation rate, and a lower chemical potential on the ͑001͒ surface. The combination of these effects results in preferential growth of 001 grains. Thus our results provide an atomistic explanation for the previously reported transition from 111 to 001 texture observed for sputter deposition of TiN in Ar/N 2 mixtures with increasing N 2 partial pressure P N 2 and at constant P N 2 with increasing N 2 ϩ /Ti flux ratios incident at the growing film.