Anodes of elemental carbon may be discharged in a galvanic cell using a molten carbonate electrolyte, a nickel-foam anode-current collector, and a porous nickel air cathode to achieve power densities of 40-100 mW/cm 2 . We report cell and anode polarization, surface area, primary particle size and a crystallization index for nine particulate carbon samples derived from fuel oil, methane, coal, charred biological material and petroleum coke. At 800 °C, current densities of 50-125 mA/cm 2 were measured at a representative cell voltage of 0.8 V. Power densities for cells with two carbon-anode materials were found to be nearly the same on scales of 2.8-and 60 cm 2 active area. Constant current operation of a small cell was accompanied by constant voltage during multiple tests of 10-30 hour duration. Cell voltage fell off after the carbon inventory was consumed. Three different cathode structures are compared, indicating that an LLNL fabricated porous nickel electrode with <10 µm pores provides improved rates compared with nickel foam with 100-300 µm pores.Petroleum coke containing substantial sulfur and ash discharges at a slightly lower rate than purified petroleum coke. The sulfur leads to degradation of the anode current collector over time. A conceptual model for electrochemical reactivity of carbon is presented which indicates the importance of (1) bulk lattice disorder, which continually provides surface reactive sites during anodic dissolution and (2) electrical conductivity, which lowers the ohmic component of anode polarization.

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A comprehensive study of different local bonding environments in boron nitride-bulk and thin filmshas been performed by core level photoabsorption. Several new features not present in crystalline reference samples are found in the absorption spectra of the thin films. These are identified as nitrogen vacancies in the hexagonal bonding of BN, nitrogen interstitials, boron clustering, sp 3-like metastable phases and sp 3 phases. Quantitative information on the concentration and distribution of point defects is easily extracted from the photoabsorption data and is discussed with regard to formation of riew phases, the B :N ratio in the films, and compared with a random model of defect formation. Information on the stability of the new bonding environments is gained by annealing the thin films. Modification of the orientation of the sp 2 hexagonal planes is attained by ion bombardment and annealing, and is monitored by angle resolved photoabsorption.

High‐strength conductive pristine graphene/epoxy composites are prepared by two simple processing methods – freeze dry/mixing and solution processing. PVP‐stabilized graphene is aggregation‐resistant and allows for excellent dispersion in both the resin and final composite, as confirmed by optical microscopy and SEM images. The superior dispersion quality results in excellent nanofiller/matrix load transfer, with a 38% increase in strength and a 37% improvement in modulus for 0.46 vol% graphene loading. The composites have a very low electrical percolation threshold of 0.088 vol%. Despite the effectiveness of both methods, the freeze‐drying method is more promising and versatile enough to be used for graphene dispersion in a wide range of other composite precursors.

Near-edge x-ray absorption fine structure (NEXAFS) has been used to study the defect content and the bonding modifications induced in BN thin films by ion implantation. The initial films were hexagonal-like BN grown on Si(100) by pulsed laser deposition. Subsequent ion implantation with N2+ at 180 keV induces the formation of a significant proportion of sp3 bonding (cubic-like), and the formation of nitrogen void defects in the remaining sp2 BN. These modifications in the bonding of a film lacking long range order can only be distinguished with a local order technique like NEXAFS.

A laser-produced x-ray drive was used to shocklessly compress solid aluminum to a peak longitudinal stress of 110 GPa within 10 ns. Interface velocities versus time for multiple sample thicknesses were measured and converted to stress density (Px-rho) using an iterative Lagrangian analysis. These are the fastest shockless compression Px(rho) results reported to date, and are stiffer than models that have been benchmarked against both static and shock-wave experiments. The present results suggest that at these short time scales there is a higher stress-dependent strength and a stiffer time-dependent inelastic response than had been expected.

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