Conductor-Insulator Interfaces in Solid Electrolytes: A Design Strategy to Enhance Li-Ion Dynamics in Nanoconfined LiBH/AlO.

Synthesizing Li-ion-conducting solid electrolytes with application-relevant properties for new energy storage devices is a challenging task that relies on a few design principles to tune ionic conductivity. When starting with originally poor ionic compounds, in many cases, a combination of several strategies, such as doping or substitution, is needed to achieve sufficiently high ionic conductivities. For nanostructured materials, the introduction of conductor-insulator interfacial regions represents another important design strategy.

Fluoride-Ion Batteries: On the Electrochemical Stability of Nanocrystalline LaBaF against Metal Electrodes.

Over the past years, ceramic fluorine ion conductors with high ionic conductivity have stepped into the limelight of materials research, as they may act as solid-state electrolytes in fluorine-ion batteries (FIBs). A factor of utmost importance, which has been left aside so far, is the electrochemical stability of these conductors with respect to both the voltage window and the active materials used. The compatibility with different current collector materials is important as well.

Redox processes in sodium vanadium phosphate cathodes - insights from operando magnetometry.

Operando magnetic susceptibility measurements of sodium ion cathode materials during repetitive electrochemical cycling enable a continuous and bulk sensitive monitoring of the transition metal oxidation states. Such measurements on NaxV2(PO4)3 identified vanadium to be the only ion undergoing oxidation/reduction processes upon battery operation. For the initial battery charging-discharging cycle as well as for the first cycle after prolonged room temperature storage, however, peculiarities within the magnetic susceptibility measurements indicate parasitic side reactions, likely on the cathode surface.

Synthesis of a tetrazine-quaterthiophene copolymer and its optical, structural and photovoltaic properties.

Herein, we report the synthesis of a novel, tetrazine-based conjugated polymer. Tetrazines have the benefit of being strong electron acceptors, while little steric hindrance is imposed on the flanking thiophene rings. Conversion of a suitably substituted nitrile precursor led to 3,6-bis(5-bromo-4-(2-octyldodecyl)thiophen-2-yl)-1,2,4,5-tetrazine (2OD-TTz).

Spatial confinement - rapid 2D F diffusion in micro- and nanocrystalline RbSnF.

Diffusion of small ions in materials with confined space for translational dynamics can be quite different to isotropic (3D) diffusion, which is found in the majority of solids. Finding credible indications for 2D diffusion is not as easy as it looks at first glance, especially if only powder samples are available. Here we chose the ternary fluoride RbSn2F5 as a new model system to seek out low-dimensional anion diffusion in a nanocrystalline material.

An Electrolyte for Reversible Cycling of Sodium Metal and Intercalation Compounds.

Na battery chemistries show poor passivation behavior of low voltage Na storage compounds and Na metal with organic carbonate-based electrolytes adopted from Li-ion batteries. Therefore, a suitable electrolyte remains a major challenge for establishing Na batteries. Here we report highly concentrated sodium bis(fluorosulfonyl)imide (NaFSI) in dimethoxyethane (DME) electrolytes and investigate them for Na metal and hard carbon anodes and intercalation cathodes.

Long-Cycle-Life Na-Ion Anodes Based on Amorphous Titania Nanotubes--Interfaces and Diffusion.

Amorphous self-assembled titania nanotube layers are fabricated by anodization in ethylene glycol based baths. The nanotubes having diameters between 70-130 nm and lengths between 4.5-17 μm are assembled in Na-ion test cells.

"Ionic liquids-in-salt"--a promising electrolyte concept for high-temperature lithium batteries?

A novel electrolyte concept for lithium-ion batteries, termed "ionic liquid-in-salt", is introduced. Our feasibility study on (1 - x)EMIMTFSI:(x)LiTFSI, 0.66 ≤ x ≤ 0.

Li ion dynamics in TiO2 anode materials with an ordered hierarchical pore structure--insights from ex situ NMR.

Ex situ Nuclear Magnetic Resonance (NMR) measurements were carried out to study lithium ion dynamics in lithium intercalated mesoporous anatase (LixTiO2) serving as an anode material for rechargeable lithium-ion batteries. As has been shown recently, hierarchically ordered TiO2 shows excellent cycling performance and ensures a high lithium storage capacity. (7)Li spin-lattice relaxation NMR and stimulated echo NMR serve as a powerful combination to shed light on the Li hopping processes from an atomic-scale point of view.

Electrochemical fabrication of Sn nanowires on titania nanotube guide layers.

We describe a novel approach for the fabrication of tailored nanowires using a two-step electrochemical process. It is demonstrated that self-organized TiO(2) nanotubes can be used to activate and guide the electrochemical growth of Sn crystallites, leading to the formation of vertical features with a high aspect ratio. We show that the dimensions and the density of Sn crystallites depend on the electrodeposition parameters.