Publications by authors named "Babak Rezaei Rad"

3 Publications

  • Page 1 of 1

High Voltage LiNiMnO/LiTiO Lithium Ion Cells at Elevated Temperatures: Carbonate- versus Ionic Liquid-Based Electrolytes.

ACS Appl Mater Interfaces 2016 Oct 23;8(39):25971-25978. Epub 2016 Sep 23.

MEET Battery Research Center, Institute for Physical Chemistry, University of Münster , Corrensstraße 46, 48149 Münster, Germany.

Thanks to its high operating voltage, the LiNiMnO (LNMO) spinel represents a promising next-generation cathode material candidate for Lithium ion batteries. However, LNMO-based full-cells with organic carbonate solvent electrolytes suffer from severe capacity fading issues, associated with electrolyte decomposition and concurrent degradative reactions at the electrode/electrolyte interface, especially at elevated temperatures. As promising alternatives, two selected LiTFSI/pyrrolidinium bis(trifluoromethane-sulfonyl)imide room temperature ionic liquid (RTIL) based electrolytes with inherent thermal stability were investigated in this work. Linear sweep voltammetry (LSV) profiles of the investigated LiTFSI/RTIL electrolytes display much higher oxidative stability compared to the state-of-the-art LiPF/organic carbonate based electrolyte at elevated temperatures. Cycling performance of the LNMO/LiTiO (LTO) full-cells with LiTFSI/RTIL electrolytes reveals remarkable improvements with respect to capacity retention and Coulombic efficiency. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns indicate maintained pristine morphology and structure of LNMO particles after 50 cycles at 0.5C. The investigated LiTFSI/RTIL based electrolytes outperform the LiPF/organic carbonate-based electrolyte in terms of cycling performance in LNMO/LTO full-cells at elevated temperatures.
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http://dx.doi.org/10.1021/acsami.6b07687DOI Listing
October 2016

Heteroatom-free arene-cobalt and arene-iron catalysts for hydrogenations.

Angew Chem Int Ed Engl 2014 Apr 24;53(14):3722-6. Epub 2014 Feb 24.

Fakultät für Chemie, Universität Regensburg, Universitätsstrasse 31, 93040 Regensburg (Germany).

75 years after the discovery of hydroformylation, cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. We have evaluated arene metalates in which the low-valent metal species is--conceptually different from heteroatom-based ligands--stabilized by π coordination to hydrocarbons. Potassium bis(anthracene)cobaltate 1 and -ferrate 2 can be viewed as synthetic precursors of quasi-"naked" anionic metal species; their aggregation is effectively impeded by (labile) coordination to the various π acceptors present in the hydrogenation reactions of unsaturated molecules (alkenes, arenes, carbonyl compounds). Kinetic studies, NMR spectroscopy, and poisoning studies of alkene hydrogenations support the formation of a homogeneous catalyst derived from 1 which is stabilized by the coordination of alkenes. This catalyst concept complements the use of complexes with heteroatom donor ligands for reductive processes.
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http://dx.doi.org/10.1002/anie.201308967DOI Listing
April 2014

A tetradentate metalloligand: synthesis and coordination behaviour of a 2-pyridyl-substituted cyclobutadiene iron complex.

Dalton Trans 2014 Mar;43(11):4247-50

University of Regensburg, Institute of Inorganic Chemistry, 93040 Regensburg, Germany.

The salt [K([18]crown-6){Cp*Fe(η(4)-C4py4)}] (K1, py = 2-pyridyl, Cp* = C5Me5) is accessible by the reaction of an iron(0) naphthalene precursor and bis(2-pyridyl)acetylene. Cyclic voltammetry and preparative investigations demonstrate the electron-rich nature of K1, which is reversibly oxidized to neutral [Cp*Fe(η(4)-C4py4)] (1) at a low potential. The first coordination studies with iron(II) and zinc(II) chloride show that all four 2-pyridyl units may be employed for metal coordination.
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http://dx.doi.org/10.1039/c3dt52699bDOI Listing
March 2014
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