Challenges and prospects of the role of solid electrolytes in the revitalization of lithium metal batteries

The scientific community is continuously committed to the search for new high energy electrochemical storage devices. In this regard, lithium metal batteries, due to their very high electrochemical energy storage capacity, appear to be a highly appealing choice. Unfortunately, the use of lithium metal as the anode may lead to some safety hazards due to its uneven deposition upon charging, resulting in dendrite growth and eventual shorting of the battery. This issue may be successfully addressed by using intrinsically safer electrolytes capable of establishing a physical barrier at the electrode interface. The most promising candidates are solid electrolytes, either polymeric or inorganic. The main purpose of this review is to describe the present status of worldwide research on these electrolyte materials together with a critical discussion of their transport properties and compatibility with metallic lithium, hoping to provide some general guidelines for the development of innovative and safe lithium metal batterie

Impedance tube measurements on the denorms round robin test material samples

The DENORMS Round Robin Test aims to study and improve the techniques used to determine the sound absorption coefficient of materials. Within this framework, samples taken from the same batch have been tested in both reverberation room and impedance tube. The latter technique presents some challenges in that the results may strongly depend on the specimen preparation and set-up. The purpose of this paper is to present the results obtained in custom-made impedance tube for the RRT set of materials. The tests have been carried out using a four-microphone impedance tube, according to the method outlined in the ASTM E2611-09 standard. The results obtained for the different parameters provided by the test, in particular the sound absorption coefficient and the sound transmission loss, are taken into account and discussed

Principles at the basis of the denorms round robin test on the low frequency sound absorption measurements in reverberation rooms and impedance tube

In recent years low frequency measurements in building and room acoustics fields gained attention. Moreover the low frequency sound absorption coefficient (below 100 Hz) has always been difficult to determine and the results coming from different laboratories cannot always be compared. This paper describes the principles at the basis of the round robin test carried out in the framework of the DENORMS cost action (Designs for Noise Reducing Materials and Structures). The same samples have been measured in reverberation rooms and in impedance tube by the different laboratories participating to the Round Robin Test.status: accepte

The DENORMS Round Robin test: Measurement procedure and post-processing of time data

The DENORMS Round Robin Test (RRT) is intended to study and improve the techniques used for the determination of the sound absorption coefficient of materials, with particular focus on the low-frequency range and on measurements in reverberation rooms. It is well known that the main reason why it is difficult to extend the frequency range of interest below 100 Hz is the low modal density. The modal behavior of a room is dependent on its geometry and this is one of the reasons why a discrepancy of the results coming from different laboratories can be found even if the same material is tested. This paper describes the measurement procedure developed to allow uniform acquisition and post-processing of acoustic response data of laboratories participating in the RRT, with and without absorbing materials inside. The tests and the post-processing operations performed on the measured data are also discussed in the paper

Hot-pressed, Dry, Nanocomposite, PEO-based Electrolyte Membranes. Ionic Conductivity Characterization and Battery Tests

http://www.electrochem.org/dl/ma/203/pdfs/0098.pd

Comparative study of the phase transition of Li1+xMn2-xO4 by anelastic spectroscopy and differential scanning calorimetry

Li1+xMn2xO4 is one of the most promising candidates as high performance cathode for lithium ion batteries. The stoichiometric compound is known to undergo a phase transition around room temperature, which has been widely studied and attributed either to Jahn–Teller effect or to charge ordering. For the applications it is important to suppress this phase transition, which lowers the electrochemical performances of the material. DSC measurements, which have been largely used in the literature to study the occurrence of the transformation, can detect a phase transition accompanied by latent heat only for x < 0.04. This fact has been generally accepted as a proof that the transformation is suppressed by doping. However, by using a technique extremely sensitive to rearrangements of atoms in the lattice, such as anelastic spectroscopy, we show that the phase transition persists up to x = 0.08, is shifted to lower temperatures, and changes its nature from first to higher order. The implications for the mechanism driving the transition and the similarities and differences with doped Fe3O4, which is the prototype of charge order transitions, are discussed

THE INTERCALATION OF LITHIUM IN NICKEL-OXIDE AND ITS ELECTROCHROMIC PROPERTIES

137103297330

How much does size really matter? Exploring the limits of graphene as Li ion battery anode material

Abstract We unravel the role of flake dimensionality on the lithiation/de-lithiation processes and electrochemical performance of anodes based on few-(FLG) and multi-layer graphene (MLG) flakes prepared by liquid phase exfoliation (LPE) of pristine graphite. The flakes are sorted by lateral size (from 380 to 75 nm) and thickness from 20 (MLG) to 2 nm (FLG) exploiting a sedimentation-based separation in centrifugal field and, finally, deposited onto Cu disks for the realization of four binder-free anodes. The electrochemical results show that decreasing lateral size and thickness leads to an increase of the initial specific capacity from ≈590 to ≈1270mAhg −1 . However, an increasing irreversible capacity is also associated to the reduction of flakes' size. We find, in addition, that the preferential Li ions storage by adsorption rather than intercalation in small lateral size

Anomalous Lattice Vibrations of Single and Few-Layer MoS2

Molybdenum disulfide (MoS2) of single and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic-force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the 3-dimensional to the 2-dimensional regime.Comment: 14 pages, 4 figure