skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Nanoscale Depth and Lithiation Dependence of V2O5 Band Structure by Cathodoluminescence Spectroscopy
Vanadium pentoxide (V2O5) is a very well-known cathode material that has attracted considerable interest for its potential use in solid-state lithium-ion batteries. We pioneer the use of depth-resolved cathodoluminescence spectroscopy (DRCLS) to monitor the changes in the electronic structure of lithiated V2O5 from the free surface to the thin film bulk several hundred nm below as a function of lithiation. DRCLS measurements of V2O5 interband transitions are in excellent agreement with density functional theory (DFT) calculations. The direct measure of V2O5's electronic band structure as a function of lithiation level provided by DRCLS can help inform solid-state battery designs to further withstand degradation and increase efficiency. In particular, these unique electrode measurements may reveal physical mechanisms of lithiation that change V2O5 irreversibly, as well as methods to mitigate them in solid-state batteries.  more » « less
Award ID(s):
1800130
PAR ID:
10165350
Author(s) / Creator(s):
Date Published:
Journal Name:
Journal of materials chemistry
Volume:
8
ISSN:
0959-9428
Page Range / eLocation ID:
11800-11810
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Journal of The Electrochemical Society)
    Pre-lithiation is the most effective method to overcome the initial capacity loss of high-capacity electrodes and has the potential to be used in beyond-conventional lithium-ion batteries. In this article we focus on two types of pre-lithiation: the first type can be applied to batteries in which the cathode has been fully lithiated but the anode has a large initial capacity loss, such as batteries made with lithium metal oxide cathode and silicon-carbon anode. The second type can be applied to batteries in which both electrodes are initially lithium-free and suffer a loss of lithium during the initial cycles, such as batteries made with sulfurized-polyacrylonitrile cathode and silicon-carbon anode. We describe the pre-lithiation procedures and electrode potential profiles during pre-lithiation corresponding to different pre-lithiation sources for both types of pre-lithiation. We also derive formulas for the theoretical specific energy and energy density that are based entirely on measurable parameters such as specific capacities, porosities, mass densities of two electrodes and extra lithium source, Coulombic efficiencies of electrodes, and the voltage of the cell. These formulas can be applied to different pre-lithiation sources to predict the specific energy of conventional and beyond-conventional lithium-ion batteries as a function of the type of pre-lithiation. 
    more » « less
  2. ; ; ; (, ECS Meeting Abstracts)
    Tracking the change in electronic structure of target elements is crucial to investigate the nature of redox reactions occurring in battery electrodes. X-ray emission spectroscopy (XES) and x-ray absorption fine structure (XAFS) perform this role well with high sensitivity and throughput, but the requisite of synchrotron facilities often limits those availability for material characterization. Using a lab-scale x-ray emission/absorption spectrometer, we investigated the changes in the local structure and chemistry around the 3d transition metal elements of LiMO 2 cathodes for Li-ion batteries as a function of the battery state of charge (SoC). Ex situ measurement was prepared from the electrode samples with discrete difference in SoC. Coupled with ex situ measurement, operando measurement was performed using pouch cells with LiMO 2 cathode, which enabled a real-time monitoring of chemical shift in an element-specific manner resulted from changing electrode potential. Through the XES mode of the bench-top spectrometer, fluorescence emissions from the LiMO 2 cathode, or the cell containing it, was monochromatized by a spherically bent crystal analyzer (SBCA). The Kβ emissions of 3d transition metal elements such as cobalt display position/shape difference of spectrum with varying SoC. The trend of chemical shift and change in spectral features provided the information on the electronic structure variation, such as oxidation state change of 3d transition metals in LiMO 2 during charge and discharge (i.e., delithiation and lithiation). Furthermore, valence-to-core (VtC) emission signals helped enable in-depth analysis such as spin structure characterization. In addition to the XES analysis, we could measure K-edge XAFS for the same 3d transition metals in LiMO 2 as well. In the XAFS mode of the spectrometer, SBCA monochromatized bremsstrahlung x-ray generated from a high-power x-ray tube is used to make an incident source energy-dispersive. While Kβ XES probed occupied levels, K-edge XAFS examined unoccupied levels providing comprehensive understanding on the change in electronic structure of 3d transition metals in LiMO 2 . Figure 1 
    more » « less
  3. ; ; ; ; ; ; (, Journal of The Electrochemical Society)
    In efforts to increase the energy density of lithium-ion batteries, researchers have attempted to both increase the thickness of battery electrodes and increase the relative fractions of active material. One system that has both of these attributes are sintered thick electrodes comprised of only active material. Such electrodes have high areal capacities, however, detailed understanding is needed of their transport properties, both electronic and ionic, to better quantify their limitations to cycling at higher current densities. In this report, efforts to improve models of the electrochemical cycling of sintered electrodes are described, in particular incorporation of matrix electronic conductivity which is dependent on the extent of lithiation of the active material and accounting for initial gradients in lithiation of active material in the electrode that develop as a consequence of transport limitations during charging cycles. Adding in these additional considerations to a model of sintered electrode discharge resulted in improved matching of experimental cell measurements. 
    more » « less
  4. ; ; ; ; ; (, Advanced Materials)
    Abstract Rechargeable secondary batteries, widely used in modern technology, are essential for mobile and consumer electronic devices and energy storage applications. Lithium (Li)‐ion batteries are currently the most popular choice due to their decent energy density. However, the increasing demand for higher energy density has led to the development of Li metal batteries (LMBs). Despite their potential, the commonly used liquid electrolyte‐based LMBs present serious safety concerns, such as dendrite growth and the risk of fire and explosion. To address these issues, using solid‐state electrolytes in batteries has emerged as a promising solution. In this Perspective, recent advancements are discussed in ionic covalent organic framework (ICOFs)‐based solid‐state electrolytes, identify current challenges in the field, and propose future research directions. Highly crystalline ion conductors with polymeric versatility show promise as the next‐generation solid‐state electrolytes. Specifically, the use of anionic or cationic COFs is examined for Li‐based batteries, highlight the high interfacial resistance caused by the intrinsic brittleness of crystalline ICOFs as the main limitation, and presents innovative ideas for developing all‐ and quasi‐solid‐state batteries using ICOF‐based solid‐state electrolytes. With these considerations and further developments, the potential for ICOFs is optimistic about enabling the realization of high‐energy‐density all‐solid‐state LMBs. 
    more » « less
  5. ; ; ; (, Small)
    Abstract Over the past decade, solid‐state batteries have garnered significant attentions due to their potentials to deliver high energy density and excellent safety. Considering the abundant sodium (Na) resources in contrast to lithium (Li), the development of sodium‐based batteries has become increasingly appealing. Sulfide‐based superionic conductors are widely considered as promising solid eletcrolytes (SEs) in solid‐state Na batteries due to the features of high ionic conductivity and cold‐press densification. In recent years, tremendous efforts have been made to investigate sulfide‐based Na‐ion conductors on their synthesis, compositions, conductivity, and the feasibility in batteries. However, there are still several challenges to overcome for their practical applications in high performance solid‐state Na batteries. This article provides a comprehensive update on the synthesis, structure, and properties of three dominant sulfide‐based Na‐ion conductors (Na3PS4, Na3SbS4, and Na11Sn2PS12), and their families that have a variety of anion and cation doping. Additionally, the interface stability of these sulfide electrolytes toward the anode is reviewed, as well as the electrochemical performance of solid‐state Na batteries based on different types of cathode materials (metal sulfides, oxides, and organics). Finally, the perspective and outlook for the development and practical utilization of sulfide‐based SE in solid‐state batteries are discussed. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email