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Results for “Synthesis Design”

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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Electronic Transport in Lithiated Iron and Bismuth Fluoride

Metal networks are formed during the lithiation of metal fluorides. Previous reports indicate that these networks are bi-continuous with the possibility to support electronic transport, though no quantitative analysis has been performed. In this study, thin films of FeF 2 and BiF 3 were chemically lithiated using n-butyllithium to form these metal networks. Direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) were utilized to find electronic conductivity and results were compared to their pure metals. Here, the results indicate films to have higher than expected conductivity value which indicates that these metal networks support electronic transport during lithiation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Rational Design of a Multifunctional Binder for High-Capacity Silicon-Based Anodes

Although several principles have been recognized to fabricate a nominal "better" binder, there continues to be a lack of a rational design and synthesis approach that would meet the robust criteria required for silicon (Si) anodes. Herein, we report a synthetic polymer binder, i.e., catechol-functionalized chitosan cross-linked by glutaraldehyde (CS-CG+GA), that serves dual functionalities: (a) wetness-resistant adhesion capability via catechol grafting and (b) mechanical robustness via in situ formation of a three-dimensional (3D) network. A SiNP-based anode with a designed functional polymer network (CS-CG10%+6%GA) exhibits a capacity retention of 91.5% after 100 cycles (2144 +/- 14 mAh/g). Properties that are traditionally considered to be advantageous, including stronger adhesion strength and higher mechanical robustness, do not always improve the binder performance. A clear relationship between these properties and ultimate electrochemical performance is established by assessing the rheological behavior, mechanical property, adhesion force, peel stress, morphology evolution, and semiquantitative evaluation. This study provides a clear path for the rational design of high-performance functional polymer binders for not only Si-based electrodes but also other types of alloy and conversion-based electrodes.

Cao, Peng-Fei↗
DOE OSTI2018

Indigo-Based Acceptor Type Small Molecules: Synthesis, Electrochemical and Optoelectronic Characterizations

In this paper, we report design and synthesis of novel low bandgap small molecules, indigo-benzimidazole (Tyr-3) and indigo-schiff base (Tyr-4) type acceptors. In these structures, tert-butoxycarbonyl (t-BOC) group has been attached to indigo nitrogen atom in order to increase the solubility. UV-vis absorption spectra of Tyr-3 and Tyr-4 dyes exhibit wide absorption bands ranging from 350 to 600 nm, indicating the relatively low bandgap giving around 2.07 eV for each. Excitation of both Tyr-3 and Tyr-4 dyes at 485 nm displays characteristic emission features of indigo moiety and also intramolecular charge transfer complex (ICT) related with their subunits. Besides increasing fluorescence quantum yields as compared to model compound, biexponential decay times for fluorescence life times were also obtained for Tyr-3 and Tyr-4 dyes. Their appropriate energy levels along with low HOMO levels are desired for light harvesting acceptors for organic solar cells when blended with poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2′,1′,3′-benzothiadiazole] (PCDTBT) as donor polymer. Photovoltaic behavior of the synthesized dyes were examined in bulk heterojunction concept and achieved photovoltaic conversion efficiencies were discussed.

74 ATOMIC AND MOLECULAR PHYSICS↗