Electrochemistry and transport properties of electrolytes modified with ferrocene redox-active ionic liquid additives

Used in their pure, undiluted form, ionic liquids usually result in Li-ion battery electrolytes with inadequate performance due low Li+ transport numbers (tLi+). Alternatively, they can be used as additives dissolved in carbonates to maintain a high tLi+ while providing the electrolyte with additional properties such as resistance to combustion, current collector passivation, and decreased Li dendritic growth. Additional properties can be imparted to the ionic liquid via the modification of their structure. Ionic liquids modified with electroactive moieties such as ferrocene (Fc-IL) can be used as an additive in Li-ion battery (LiB) electrolytes to prevent cathode over-oxidation via the redox shuttle mechanism. The aim of the present work is to evaluate the properties of LiB electrolytes modified with such Fc-IL at different concentrations. At low concentrations (0.3–0.5 mol/L), the redox-active ionic liquid behaves as expected for a redox shuttle. We show that at 1 mol/L, however, the redox ionic liquid yields a different discharge behavior after the overcharging step, providing an increase in discharge capacity. This behavior is linked to the deposition of the ferrocenium-IL at the positive electrode. Such electrolyte is non-flammable and is highly efficient to achieve shuttling of excess charge. Based on this principle, it is expected that novel ionic liquids can be designed for development of other types of additives and contribute to developing safer battery electrolytes. As a part of this commemorative issue, this contribution highlights the type of collaborative research currently being done on energy storage devices at the Department of Chemistry at the Université de Montréal.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Synthesis, characterization and hydrogen sorption properties of a Body Centered Cubic 42Ti–21V–37Cr alloy doped with Zr7Ni10

The morphology, crystal structure, and hydrogenation properties of the alloy 42Ti–21V–37Cr doped with 4 wt.% of Zr7Ni10 were investigated. Two doping schemes were used: (i) a single melt method, where all the components were melted together; (ii) a co-melt method where 42Ti–21V–37Cr alloy and Zr7Ni10 were first melted separately and thereafter re-melted together. The single melt alloy was a multi-phase compound, made of two intergranular phases within a Ti-, V-, Cr-rich matrix. One intergranular phase was Ti-, Zr-, Ni-rich and the other one Ti-rich. The co-melt alloy was a two phase material; a Ti-, V-, Cr-rich matrix and an homogeneously distributed Ti-, Zr-, Ni-rich intergranular phase.Both single melt and co-melt samples have a faster and more complete first hydrogenation (activation) than the undoped 42Ti–21V–37Cr. Activation is complete in less than 3 min for both doped alloys and their thermodynamics parameters are similar

Replacement of vanadium by ferrovanadium in a Ti-based body centred cubic (BCC) alloy: towards a low-cost hydrogen storage material

We report here the effect on hydrogen sorption behavior of replacing vanadium by ferrovanadium (FeV) in Ti-V-Cr Body Centred Cubic (BCC) solid solution alloys. The compositions studied were Ti1.56V0.36Cr1.08 and Ti1.26V0.63Cr1.11. Both of the alloys were synthesized by melting with 4 wt % of Zr7Ni10 in order to enhance the first hydrogenation (i.e., activation) kinetics. The ferrovanadium substitution leads to the same microstructure as the vanadium pristine alloys and no significant change in the lattice parameters was found. However, a longer incubation time was observed in the activation process for the FeV substituted alloy. Finally, the replacement of vanadium by ferrovanadium did not have a noticeable impact on the hydrogen capacities, heat of formation, and entropy

Synthesis, characterization and hydrogen sorption properties of a Body Centered Cubic 42Ti–21V–37Cr alloy doped with Zr7Ni10

The morphology, crystal structure, and hydrogenation properties of the alloy 42Ti–21V–37Cr doped with 4 wt.% of Zr7Ni10 were investigated. Two doping schemes were used: (i) a single melt method, where all the components were melted together; (ii) a co-melt method where 42Ti–21V–37Cr alloy and Zr7Ni10 were first melted separately and thereafter re-melted together. The single melt alloy was a multi-phase compound, made of two intergranular phases within a Ti-, V-, Cr-rich matrix. One intergranular phase was Ti-, Zr-, Ni-rich and the other one Ti-rich. The co-melt alloy was a two phase material; a Ti-, V-, Cr-rich matrix and an homogeneously distributed Ti-, Zr-, Ni-rich intergranular phase.Both single melt and co-melt samples have a faster and more complete first hydrogenation (activation) than the undoped 42Ti–21V–37Cr. Activation is complete in less than 3 min for both doped alloys and their thermodynamics parameters are similar

Performance of Cu-coated vanadium cans for in situ neutron powder diffraction experiments on hydrogen storage materials

In situ neutron powder diffraction (NPD) measurements of hydrogenation processes taking place at high temperatures pose difficulties related to the choice of sample can material. This article describes a simple design for a copper-coated vanadium can and its connection to the gas-handling system, tested up to 523 K. High-quality NPD patterns of TiV1.2Mn0.8 body-centred cubic alloy, as-cast and partially hydrogenated, were collected at 373 K and deuterium pressures up to 2 bar (200 kPa).Peer reviewed: YesNRC publication: Ye