Recent studies have shown a current limiting effect in the field emission behavior of carbon nanotubes. In this letter, we demonstrate that an individual nanotube exhibits current saturation above 100 nA of emission current, and we show that this current saturation is a direct result of an adsorbate-enhanced field emission mechanism. Current saturation results from the displacement of adsorbates from configurations of tunneling enhancement as electric field and current are increased. Saturation is concurrent with rapid fluctuations in emission current and distinctive changes in the field emission patterns. At high fields, the adsorbate states are completely removed from the nanotube. A single, clean single-walled nanotube shows no evidence of current saturation for emission currents reaching 2 μA.

We demonstrate long-term field emission stability from single-walled carbon nanotubes. Unballasted nanotubes operate without degradation for over 350 h at 10−9 Torr. Nanotubes are shown to be significantly less sensitive to operating environments than metallic emitters. In 10−7 Torr of H2O, we demonstrate 100 h of continuous bias field emission with no current degradation. Protrusion growth and current runaway, typical problems for unballasted metal emitters, are not observed with nanotubes. Single-walled nanotubes do show susceptibility to damage by oxidation. We suggest that the exceptional environmental stability of carbon nanotubes is due to a combination of geometry, strong carbon bonding, and the lack of protrusion growth.

Multilayer indium-tin-oxide (ITO)–Ag–ITO stacks were evaluated as transparent conductors for flexible organic light-emitting diode (OLED) displays. The ITO–metal–ITO (IMI) samples exhibited significantly reduced sheet resistance over ITO and greater than 80% optical transmission. The IMI films deposited on plastic substrates showed dramatically improved mechanical properties when subjected to bending both as a function of radius of curvature as well as number of cycles to a fixed radius. OLEDs were fabricated on both ITO and IMI anodes, and the devices with IMI anodes showed improved performance at current densities greater than 1mA∕cm2 due to the improved conductivity of the anode.

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Energy storage systems with Li-ion batteries are increasingly deployed to maintain a robust and resilient grid and facilitate the integration of renewable energy resources. However, appropriate selection of cells for different applications is difficult due to limited public data comparing the most commonly used off-the-shelf Li-ion chemistries under the same operating conditions. This article details a multi-year cycling study of commercial LiFePO4 (LFP), LiNixCoyAl1−x−yO2 (NCA), and LiNixMnyCo1−x−yO2 (NMC) cells, varying the discharge rate, depth of discharge (DOD), and environment temperature. The capacity and discharge energy retention, as well as the round-trip efficiency, were compared. Even when operated within manufacturer specifications, the range of cycling conditions had a profound effect on cell degradation, with time to reach 80% capacity varying by thousands of hours and cycle counts among cells of each chemistry. The degradation of cells in this study was compared to that of similar cells in previous studies to identify universal trends and to provide a standard deviation for performance. All cycling files have been made publicly available at batteryarchive.org, a recently developed repository for visualization and comparison of battery data, to facilitate future experimental and modeling efforts.