Specific energy

About: Specific energy is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 50908 citations. The topic is also known as: energy density & massic energy.

Carbon dioxide splitting in a dielectric barrier discharge plasma: a combined experimental and computational study.

Abstract: Plasma technology is gaining increasing interest for the splitting of CO2 into CO and O2 . We have performed experiments to study this process in a dielectric barrier discharge (DBD) plasma with a wide range of parameters. The frequency and dielectric material did not affect the CO2 conversion and energy efficiency, but the discharge gap can have a considerable effect. The specific energy input has the most important effect on the CO2 conversion and energy efficiency. We have also presented a plasma chemistry model for CO2 splitting, which shows reasonable agreement with the experimental conversion and energy efficiency. This model is used to elucidate the critical reactions that are mostly responsible for the CO2 conversion. Finally, we have compared our results with other CO2 splitting techniques and we identified the limitations as well as the benefits and future possibilities in terms of modifications of DBD plasmas for greenhouse gas conversion in general.

Nanostructured Li2S–C Composites as Cathode Material for High-Energy Lithium/Sulfur Batteries

Abstract: With a theoretical capacity of 1166 mA·h·g–1, lithium sulfide (Li2S) has received much attention as a promising cathode material for high specific energy lithium/sulfur cells. However, the insulating nature of Li2S prevents the achievement of high utilization (or high capacity) and good rate capability. Various efforts have been made to ameliorate this problem by improving the contact between Li2S and electronic conductors. In the literature, however, a relatively high capacity was only obtained with the Li2S content below 50 wt %; therefore, the estimated cell specific energy values are often below 350 W·h·kg–1, which is insufficient to meet the ever-increasing requirements of newly emerging technologies. Here, we report a cost-effective way of preparing nanostructured Li2S-carbon composite cathodes by high-energy dry ball milling of commercially available micrometer-sized Li2S powder together with carbon additives. A simple but effective electrochemical activation process was used to dramatically improv...

O2(Δ1) production in He∕O2 mixtures in flowing low pressure plasmas

Abstract: Chemical oxygen-iodine lasers (COIL) are attractive for diverse industrial applications because they are capable of high efficiency, high power operation, and because the 1.315μm wavelength can be transmitted through fiber optics and couples efficiently with most metals. Conventional COILs are pumped with O2(Δ1) that is generated by reaction of Cl2 in a basic H2O2 solution. Current trends in pumping COILs involve producing the O2(Δ1) in electric discharges, thereby circumventing the hazards, complexity, and weight associated with pumping and storing caustic liquids. In this work, we have investigated the scaling of O2(Δ1) yields with specific energy deposition in He∕O2 mixtures in flowing radio frequency (rf) discharges at pressures of a few to tens of Torr using a global plasma kinetics model. We found that O2(Δ1) yield increases nearly linearly with specific energy deposition in O2 molecules up to a few eV per molecule, with yields peaking around 30% by 5–8eV. Further increases in specific energy deposi...

Comparison of electrical discharge techniques for nonthermal plasma processing of NO in N/sub 2/

Abstract: This paper presents a comparative assessment of three types of electrical discharge reactors: 1) pulsed corona, 2) dielectric-barrier discharge, and 3) dielectric-pellet bed reactor. The emphasis is on the efficiency for electron-impact dissociation of N/sub 2/(e+N/sub 2//spl rarr/e+N+N) and the subsequent chemical reduction of NO by nitrogen atoms (N+NO/spl rarr/N/sub 2/+O). By measuring the concentration of NO as a function of input energy density in dilute mixtures of NO in N/sub 2/, it is possible to determine the specific energy cost for the dissociation of N/sub 2/. Our experimental results show that the specific energy consumption (eV per NO molecule reduced) of different types of electrical discharge reactors are all similar. These results imply that, during radical production in electrical discharge reactors, the electric field experienced by the plasma is space-charge shielded to approximately the same value. The specific energy consumption for the dissociation of N/sub 2/ using electrical discharge processing is measured to be around 240 eV per nitrogen atom produced. In the NO-N/sub 2/ mixture, this corresponds to a specific energy consumption of around 240 eV per NO molecule reduced. >