4 research outputs found
Room-temperature cycling of metal fluoride electrodes: Liquid electrolytes for high-energy fluoride ion cells
Fluoride ion batteries are potential “next-generation” electrochemical storage devices that offer high energy density. At present, such batteries are limited to operation at high temperatures because suitable fluoride ion–conducting electrolytes are known only in the solid state. We report a liquid fluoride ion–conducting electrolyte with high ionic conductivity, wide operating voltage, and robust chemical stability based on dry tetraalkylammonium fluoride salts in ether solvents. Pairing this liquid electrolyte with a copper–lanthanum trifluoride (Cu@LaF_3) core-shell cathode, we demonstrate reversible fluorination and defluorination reactions in a fluoride ion electrochemical cell cycled at room temperature. Fluoride ion–mediated electrochemistry offers a pathway toward developing capacities beyond that of lithium ion technology
Reactivity of 3d Transition Metal Cations in Diethylene Glycol Solutions. Synthesis of Transition Metal Ferrites with the Structure of Discrete Nanoparticles Complexed with Long-Chain Carboxylate Anions
Intrinsic Chirality Origination in Carbon Nanotubes
Elucidating
the origin of carbon nanotube chirality is key for
realizing their untapped potential. Currently, prevalent theories
suggest that catalyst structure originates chirality <i>via</i> an epitaxial relationship. Here we studied chirality abundances
of carbon nanotubes grown on floating liquid Ga droplets, which excludes
the influence of catalyst features, and compared them with abundances
grown on solid Ru nanoparticles. Results of growth on liquid droplets
bolsters the intrinsic preference of carbon nuclei toward certain
chiralities. Specifically, the abundance of the (11,1)/χ = 4.31°
tube can reach up to 95% relative to (9,4)/χ = 17.48°,
although they have exactly the same diameter, (9.156 Ă…). However,
the comparative abundances for the pair, (19,3)/χ = 7.2°
and (17,6)/χ = 14.5°, with bigger diameter, (16.405 Å),
fluctuate depending on synthesis temperature. The abundances of the
same pairs of tubes grown on floating solid polyhedral Ru nanoparticles
show completely different trends. Analysis of abundances in relation
to nucleation probability, represented by a product of the Zeldovich
factor and the deviation interval of a growing nuclei from equilibrium
critical size, explain the findings. We suggest that the chirality
in the nanotube in general is a result of interplay between intrinsic
preference of carbon cluster and induction by catalyst structure.
This finding can help to build the comprehensive theory of nanotube
growth and offers a prospect for chirality-preferential synthesis
of carbon nanotubes by the exploitation of liquid catalyst droplets