Effect of Salt Concentration on the Interfacial Solvation Structure and Early Stage of Solid-Electrolyte Interphase Formation in Ca(BH)/THF for Ca Batteries.

The Ca solvation structure at the electrolyte/electrode interface is of central importance to understand electroreduction stability and solid-electrolyte interphase (SEI) formation for the novel multivalent Ca battery systems. Using an exemplar electrolyte, the concentration-dependent solvation structure of Ca(BH)-tetrahydrofuran on a gold model electrode has been investigated with various electrolyte concentrations via electrochemical quartz crystal microbalance with dissipation (EQCM-D) and X-ray photoelectron spectroscopy (XPS). For the first time, in situ EQCM-D results prove that the prevalent species adsorbed at the interface is CaBH across all concentrations.

Toward practical issues: Identification and mitigation of the impurity effect in glyme solvents on the reversibility of Mg plating/stripping in Mg batteries.

Reversible electrochemical magnesium plating/stripping processes are important for the development of high-energy-density Mg batteries based on Mg anodes. Ether glyme solutions such as monoglyme (G1), diglyme (G2), and triglyme (G3) with the MgTFSI salt are one of the conventional and commonly used electrolytes that can obtain the reversible behavior of Mg electrodes. However, the electrolyte cathodic efficiency is argued to be limited due to the enormous parasitic reductive decomposition and passivation, which is governed by impurities.

Energy storage emerging: A perspective from the Joint Center for Energy Storage Research.

Energy storage is an integral part of modern society. A contemporary example is the lithium (Li)-ion battery, which enabled the launch of the personal electronics revolution in 1991 and the first commercial electric vehicles in 2010. Most recently, Li-ion batteries have expanded into the electricity grid to firm variable renewable generation, increasing the efficiency and effectiveness of transmission and distribution.

Quantification of the Mass and Viscoelasticity of Interfacial Films on Tin Anodes Using EQCM-D.

Electrochemical quartz crystal microbalance coupled with dissipation (EQCM-D) is employed to investigate the solid electrolyte interphase (SEI) formation and Li insertion/deinsertion into thin film electrodes of tin. Based on the frequency change we find that the initial SEI formation process is rapid before Li insertion but varies significantly with increasing concentration of the additive fluoroethylene carbonate (FEC) in the electrolyte. The extent of dissipation, which represents the film rigidity, increases with cycle number, reflecting film thickening and softening.

Investigation of fluoroethylene carbonate effects on tin-based lithium-ion battery electrodes.

Electroless plating of tin on copper foil (2-D) and foams (3-D) was used to create carbon- and binder-free thin films for solid electrolyte interphase (SEI) property investigation. When electrochemically cycled vs lithium metal in coin cells, the foam electrodes exhibited better cycling performance than the planar electrodes due to electrode curvature. The effect of the additive/cosolvent fluoroethylene carbonate (FEC) was found to drastically improve the capacity retention and Coulombic efficiency of the cells.

Conjugated polymer energy level shifts in lithium-ion battery electrolytes.

The ionization potentials (IPs) and electron affinities (EAs) of widely used conjugated polymers are evaluated by cyclic voltammetry (CV) in conventional electrochemical and lithium-ion battery media, and also by ultraviolet photoelectron spectroscopy (UPS) in vacuo. By comparing the data obtained in the different systems, it is found that the IPs of the conjugated polymer films determined by conventional CV (IPC) can be correlated with UPS-measured HOMO energy levels (EH,UPS) by the relationship EH,UPS = (1.14 ± 0.

Full-field synchrotron tomography of nongraphitic foam and laminate anodes for lithium-ion batteries.

Nondestructive methods that allow researchers to gather high-resolution quantitative information on a material's physical properties from inside a working device are increasingly in demand from the scientific community. Synchrotron-based microcomputed X-ray tomography, which enables the fast, full-field interrogation of materials in functional, real-world environments, was used to observe the physical changes of next-generation lithium-ion battery anode materials and architectures. High capacity, nongraphitic anodes were chosen for study because they represent the future direction of the field and one of their recognized limitations is their large volume expansion and contraction upon cycling, which is responsible for their generally poor electrochemical performance.

Morphological and crystalline evolution of nanostructured MnO2 and its application in lithium--air batteries.

Single-crystal α-MnO(2) nanotubes have been successfully synthesized by microwave-assisted hydrothermal of potassium permanganate in the presence of hydrochloric acid. The growth mechanism including the morphological and crystalline evolution has been carefully studied with time-dependent X-ray diffraction, electron microscopy, and controlled synthesis. The as-synthesized MnO(2) nanostructures are incorporated in air cathodes of lithium--air batteries as electrocatalysts for the oxygen reduction and evolution reactions.

Electrodeposited bismuth telluride nanowire arrays with uniform growth fronts.

Bismuth telluride (Bi2Te3) nanowires were deposited into porous alumina templates with 35 nm diameter pores by a pulsed-potential electrodeposition method. For growth at temperatures between 1 and 4 degrees C, the nanowires filled 93% of the pores of the template, and the growth fronts were uniform with nanowire lengths of approximately 62-68 microm. There are over ten billion nanowires per square centimeter with aspect ratios approaching 2000:1.