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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Rechargeability and economic aspects of alkaline zinc-manganese dioxide cells for electrical storage and load leveling

Batteries based on manganese dioxide (MnO2) cathodes are good candidates for grid-scale electrical energy storage, as MnO2 is low-cost, relatively energy dense, safe, water-compatible, and non-toxic. Alkaline Zn-MnO2 cells, if cycled at reduced depth of discharge (DOD), have been found to achieve substantial cycle life with battery costs projected to be in the range of $100 to 150 per kWh (delivered). Commercialization of rechargeable Zn-MnO2 batteries has in the past been hampered due to poor cycle life. In view of this, the work reported here focuses on the long-term rechargeability of prismatic MnO2 cathodes at reduced DOD when exposed to the effects of Zn anodes and with no additives or specialty materials. Over 3000 cycles is shown to be obtainable at 10% DOD with energy efficiency >80%. The causes of capacity fade during long-term cycling are also investigated and appear to be mainly due to the formation of irreversible manganese oxides in the cathode. Analysis of the data indicates that capacity loss is rapid in the first 250 cycles, followed by a regime of stability that can last for thousands of cycles. A model has been developed that captures the behavior of the cells investigated using measured state of charge (SOC) data as input. An approximate economic analysis is also presented to evaluate the economic viability of Zn-MnO2 batteries based on the experiments reported here. (C) 2014 Elsevier B.V. All rights reserved.

Ingale, ND↗
DOE OSTI2019

Impact of Ni and Mg Loadings on Dry Reforming Performance of Pt/Ceria-Zirconia Catalysts

The isolated effects of Ni and Mg on a series of Pt/Ce 0.6 Zr 0.4 O 2 (CZO) reforming catalysts were evaluated and used to formulate an improved catalyst with both Ni and Mg present. The dry reforming reaction results indicate that Ni enhances the CH 4 conversion at low temperatures while Mg improves the H 2 :CO ratio and stability, but requires high temperatures to reach similar conversions. The detection of coke (5.5 X 10 -4 g/g cat •h) over the 2.7Ni-CZO sample led to the examination of the 2.7Ni-0.50Mg-CZO sample. The catalyst activity results and the absence of coke formation over the 2.7Ni-0.50Mg-CZO sample confirmed that both Ni and Mg are needed to obtain a balance between catalyst activity and stability. The catalysts tested yielded low temperature activity with 10 % CH 4 conversions at temperature <500 °C. Furthermore, this work provides key insights into the proper design of low temperature reforming catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Broad Substrate Specificity of the Loading Didomain of the Lipomycin Polyketide Synthase

LipPks1, a polyketide synthase subunit of the lipomycin synthase, is believed to catalyze the polyketide chain initiation reaction using isobutyryl-CoA as a substrate, followed by an elongation reaction with methylmalonyl-CoA to start the biosynthesis of antibiotic alpha-lipomycin in Streptomyces aureofaciens Tu117. Recombinant LipPks1, containing the thioesterase domain from the 6-deoxyerythronolide B synthase, was produced in Escherichia coli, and its substrate specificity was investigated in vitro. Surprisingly, several different acyl-CoAs, including isobutyryl-CoA, were accepted as the starter substrates, while no product was observed with acetyl-CoA. These results demonstrate the broad substrate specificity of LipPks1 and may be applied to producing new antibiotics.

Yuzawa, S↗