Paramagnetic salt and agarose recipes for phantoms with desired T1 and T2 values for low-field MRI.

Tissue-mimicking reference phantoms are indispensable for the development and optimization of magnetic resonance (MR) measurement sequences. Phantoms have greatest utility when they mimic the MR signals arising from tissue physiology; however, many of the properties underlying these signals, including tissue relaxation characteristics, can vary as a function of magnetic field strength. There has been renewed interest in magnetic resonance imaging (MRI) at field strengths less than 1 T, and phantoms developed for higher field strengths may not be physiologically relevant at these lower fields.

NMR studies of polymeric sodium ion conductors-a brief review.

Sodium has long been considered an alternative active battery cation to lithium because of the chemical similarity and the overwhelming natural abundance of Na compared to Li. In the "early days" of poly (ethylene oxide) (PEO) and alkali metal salt complexes proposed as polymer electrolytes, studies of Na-salt/PEO materials were nearly as prevalent as those of lithium analogues. Fast forwarding to the present day, there is growing interest in sodium battery chemistry spurred by the challenges of continued advancement in lithium-based batteries.

Sodium Rich Vanadium Oxy-Fluorophosphate - Na Ni V (PO ) F O - as Advanced Cathode for Sodium Ion Batteries.

Conventional sodium-based layered oxide cathodes are extremely air sensitive and possess poor electrochemical performance along with safety concerns when operating at high voltage. The polyanion phosphate, Na V (PO ) stands out as an excellent candidate due to its high nominal voltage, ambient air stability, and long cycle life. The caveat is that Na V (PO ) can only exhibit reversible capacities in the range of 100 mAh g , 20% below its theoretical capacity.

Broadband NMR Relaxometry as a Powerful Technique to Study Molecular Dynamics of Ionic Liquids.

Fast field cycling nuclear magnetic resonance (FFC NMR) relaxometry technique has been demonstrated to be a useful analytical tool to investigate molecular dynamics in very diverse systems during the last decades. Of particular importance has been its application in studying ionic liquids, upon which this review article is based. Some of the research carried out on ionic liquids during the last ten years using this technique is highlighted in this article with the aim of promoting the favorable features of FFC NMR applied toward understanding dynamics of complex systems.

Acid-in-Clay Electrolyte for Wide-Temperature-Range and Long-Cycle Proton Batteries.

Proton conduction underlies many important electrochemical technologies. A family of new proton electrolytes is reported: acid-in-clay electrolyte (AiCE) prepared by integrating fast proton carriers in a natural phyllosilicate clay network, which can be made into thin-film (tens of micrometers) fluid-impervious membranes. The chosen example systems (sepiolite-phosphoric acid) rank top among the solid proton conductors in terms of proton conductivities (15 mS cm at 25 °C, 0.

A high-performance hydroxide exchange membrane enabled by Cu-crosslinked chitosan.

Ion exchange membranes are widely used to selectively transport ions in various electrochemical devices. Hydroxide exchange membranes (HEMs) are promising to couple with lower cost platinum-free electrocatalysts used in alkaline conditions, but are not stable enough in strong alkaline solutions. Herein, we present a Cu-crosslinked chitosan (chitosan-Cu) material as a stable and high-performance HEM.

Nanoscale Hybrid Electrolytes with Viscosity Controlled Using Ionic Stimulus for Electrochemical Energy Conversion and Storage.

As renewable energy is rapidly integrated into the grid, the challenge has become storing intermittent renewable electricity. Technologies including flow batteries and CO conversion to dense energy carriers are promising storage options for renewable electricity. To achieve this technological advancement, the development of next generation electrolyte materials that can increase the energy density of flow batteries and combine CO capture and conversion is desired.

Dynamics of Glyceline and Interactions of Constituents: A Multitechnique NMR Study.

The dynamics of the organic components of the deep eutectic solvent (DES) glyceline are analyzed using an array of complementary nuclear magnetic resonance (NMR) methods. Fast-field cycling H relaxometry, pulsed field gradient diffusion, nuclear overhauser effect spectroscopy (NOESY), C NMR relaxation, and pressure-dependent NMR experiments are deployed to sample a range of frequencies and modes of motion of the glycerol and choline components of the DES. Generally, translational and rotational diffusion of glycerol are more rapid than those of choline while short-range rotational motions observed from C relaxation indicate slow local motion of glycerol at low choline chloride (ChCl) content.

CO utilization in built environment the swing carbonation of alkaline solid wastes with different mineralogy.

Carbon mineralization to solid carbonates is one of the reaction pathways that can not only utilize captured CO2 but also potentially store it in the long term. In this study, the dissolution and carbonation behaviors of alkaline solid wastes (i.e.

Li-Ion Diffusion in Nanoconfined LiBH-LiI/AlO: From 2D Bulk Transport to 3D Long-Range Interfacial Dynamics.

Solid electrolytes based on LiBH receive much attention because of their high ionic conductivity, electrochemical robustness, and low interfacial resistance against Li metal. The highly conductive hexagonal modification of LiBH can be stabilized via the incorporation of LiI. If the resulting LiBH-LiI is confined to the nanopores of an oxide, such as AlO, interface-engineered LiBH-LiI/AlO is obtained that revealed promising properties as a solid electrolyte.

NMR Relaxometry and Diffusometry Analysis of Dynamics in Ionic Liquids and Ionogels for Use in Lithium-Ion Batteries.

We have investigated the charge transport dynamics of a novel solid-like electrolyte material based on mixtures of the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM] TFSI) and various concentrations of lithium salt bis(trifluoromethylsulfonyl)imide (LiTFSI) confined within a SiO matrix, prepared via a sol-gel method. The translational diffusion coefficients of BMIM, TFSI, and Li in ILs and confined ILs (ionogels, IGs) with different concentrations of lithium salt have been measured at variable temperatures, covering the 20-100 °C range, using nuclear magnetic resonance (NMR) pulsed field gradient diffusion spectroscopy. The mobility of BMIM, TFSI, and Li was found to increase with the [BMIM] TFSI/LiTFSI ratio, exhibiting an almost liquid-like mobility in IGs.

Improved Anisotropic Thermoelectric Behavior of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) via Magnetophoresis.

There is strong demand for achieving morphological control of conducting polymers in its many potential applications, from energy harvesting to spintronics. Here, the static magnetic-field-induced alignment of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) particles is demonstrated. PEDOT:PSS thin films cast under modest mT-level magnetic fields exhibit a fourfold increase in the Seebeck coefficient and doubled electrical conductivity.

Polymer Capacitor Dielectrics for High Temperature Applications.

Much effort has been invested for nearly five decades to identify and develop new polymer capacitor dielectrics for higher than ambient temperature applications. Simultaneous demands of processability, dielectric permittivity, thermal conductivity, and dielectric breakdown strength dictated by increasing high power performance criteria limit the number of available materials. The present review first explains the advantages of metallized polymer film capacitors over the film-foil, ceramic, and electrolytic counterparts and then presents a comprehensive review on both past developmental effort of commercial resins and recent research progress on new polymers targeted for operating temperature above 150 °C.

Enhanced Lithium Oxygen Battery Using a Glyme Electrolyte and Carbon Nanotubes.

The lithium oxygen battery has a theoretical energy density potentially meeting the challenging requirements of electric vehicles. However, safety concerns and short lifespan hinder its application in practical systems. In this work, we show a cell configuration, including a multiwalled carbon nanotube electrode and a low flammability glyme electrolyte, capable of hundreds of cycles without signs of decay.

Correlating Li-Solvation Structure and its Electrochemical Reaction Kinetics with Sulfur in Subnano Confinement.

Combining theoretical and experimental approaches, we investigate the solvation properties of Li ions in a series of ether solvents (dimethoxyethane, diglyme, triglyme, tetraglyme, and 15-crown-5) and their subsequent effects on the solid-state lithium-sulfur reactions in subnano confinement. The ab initio and classical molecular dynamics (MD) simulations predict Li ion solvation structures within ether solvents in excellent agreement with experimental evidence from electrospray ionization-mass spectroscopy. An excellent correlation is also established between the Li-solvation binding energies from the ab initio MD simulations and the lithiation overpotentials obtained from galvanostatic intermittent titration techniques (GITT).

Anisotropic Ion Diffusion and Electrochemically Driven Transport in Nanostructured Block Copolymer Electrolytes.

Nanostructured block copolymer electrolytes have the potential to enable solid-state batteries with lithium metal anodes. We present complete continuum characterization of ion transport in a lamellar polystyrene-b-poly(ethylene oxide) copolymer/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte as a function of salt concentration. Electrochemical measurements are used to determine the Stefan-Maxwell salt diffusion coefficients [Formula: see text], [Formula: see text], and [Formula: see text].

Connection between Lithium Coordination and Lithium Diffusion in [Pyr ][FTFSI] Ionic Liquid Electrolytes.

The use of highly concentrated ionic liquid-based electrolytes results in improved rate capability and capacity retention at 20 °C compared to Li -dilute systems in Li-metal and Li-ion cells. This work explores the connection between the bulk electrolyte properties and the molecular organization to provide insight into the concentration dependence of the Li transport mechanisms. Below 30 mol %, the Li -containing species are primarily smaller complexes (one Li cation) and the Li ion transport is mostly derived from the vehicular transport.

Defect chemistry and electrical properties of garnet-type LiLaZrO.

Garnet-type cubic LiLaZrO exhibits one of the highest lithium-ion conductivity values amongst oxides (up to ∼2 mS cm at room temperature). This compound has also emerged as a promising candidate for solid electrolytes in all-solid-state lithium batteries, due to its high ionic conductivity, good chemical stability against lithium metal, and wide electrochemical stability window. Defect chemistry of this class of materials, although less studied, is critical to the understanding of the nature of ionic conductivity and predicting the properties of grain boundaries and heterogeneous solid interfaces.

Polymeric peptide pigments with sequence-encoded properties.

Melanins are a family of heterogeneous polymeric pigments that provide ultraviolet (UV) light protection, structural support, coloration, and free radical scavenging. Formed by oxidative oligomerization of catecholic small molecules, the physical properties of melanins are influenced by covalent and noncovalent disorder. We report the use of tyrosine-containing tripeptides as tunable precursors for polymeric pigments.

Solvation behavior of carbonate-based electrolytes in sodium ion batteries.

Sodium ion batteries are on the cusp of being a commercially available technology. Compared to lithium ion batteries, sodium ion batteries can potentially offer an attractive dollar-per-kilowatt-hour value, though at the penalty of reduced energy density. As a materials system, sodium ion batteries present a unique opportunity to apply lessons learned in the study of electrolytes for lithium ion batteries; specifically, the behavior of the sodium ion in an organic carbonate solution and the relationship of ion solvation with electrode surface passivation.

NMR Studies of Solvent-Free Ceramic Composite Polymer Electrolytes-A Brief Review.

Polyether-based polymer electrolytes containing ceramic inorganic oxide fillers often exhibit improved mechanical and ion transport properties compared to their filler-free counterparts. The nature of local scale interactions that give rise to these enhanced properties is explored by nuclear magnetic resonance measurements.

Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids.

We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate.

Solid-State Nuclear Magnetic Resonance Studies of Electrochemically Discharged CF(x).

Electrochemical studies of three types of CF(x) (F - Fiber based, C - Petroleum coke based, G - Graphite based) have demonstrated different electrochemical performances types in previous work, with fiber based CF(x) delivering superior performance over those based on petroleum coke and graphite. (13)C and (19)F MAS (Magic Angle Spinning) NMR techniques are employed to identify the atomic/molecular structural factors that might account for differences in electrochemical performance among the different types of CF(x). Small quantitative variations of covalent CF and LiF are noted as a function of discharge and sp(3) bonded carbons are detected in discharged F type of CF(x).

Nuclear magnetic resonance study of the dynamics of imidazolium ionic liquids with -CH2Si(CH3)3 vs -CH2C(CH3)3 substituents.

Trimethylsilylmethyl (TMSiM)-substituted imidazolium bis(trifluoromethylsulfonyl)imide (NTf(2)-), and tetrafluoroborate (BF(4)-) ionic liquids (ILs) have lower room-temperature viscosities by factors of 1.6 and 7.4, respectively, than isostructural neopentylimidazolium ILs.