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


Title: Tension‐Induced Cavitation in Li‐Metal Stripping
Abstract Designing stable Li metal and supporting solid structures (SSS) is of fundamental importance in rechargeable Li‐metal batteries. Yet, the stripping kinetics of Li metal and its mechanical effect on the supporting solids (including solid electrolyte interface) remain mysterious to date. Here, through nanoscale in situ observations of a solid‐state Li‐metal battery in an electron microscope, two distinct cavitation‐mediated Li stripping modes controlled by the ratio of the SSS thickness (t) to the Li deposit's radius (r) are discovered. A quantitative criterion is established to understand the damage tolerance of SSS on the Li‐metal stripping pathways. For mechanically unstable SSS (t/r < 0.21), the stripping proceeds via tension‐induced multisite cavitation accompanied by severe SSS buckling and necking, ultimately leading to Li “trapping” or “dead Li” formation; for mechanically stable SSS (t/r > 0.21), the Li metal undergoes nearly planar stripping from the root via single cavitation, showing negligible buckling. This work proves the existence of an electronically conductive precursor film coated on the interior of solid electrolytes that however can be mechanically damaged, and it is of potential importance to the design of delicate Li‐metal supporting structures to high‐performance solid‐state Li‐metal batteries.  more » « less
Award ID(s):
2034902
PAR ID:
10474523
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Advanced Materials
Volume:
35
Issue:
7
ISSN:
0935-9648
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Advanced Science)
    Abstract As solid‐state batteries (SSBs) with lithium (Li) metal anodes gain increasing traction as promising next‐generation energy storage systems, a fundamental understanding of coupled electro‐chemo‐mechanical interactions is essential to design stable solid‐solid interfaces. Notably, uneven electrodeposition at the Li metal/solid electrolyte (SE) interface arising from intrinsic electrochemical and mechanical heterogeneities remains a significant challenge. In this work, the thermodynamic origins of mechanics‐coupled reaction kinetics at the Li/SE interface are investigated and its implications on electrodeposition stability are unveiled. It is established that the mechanics‐driven energetic contribution to the free energy landscape of the Li deposition/dissolution redox reaction has a critical influence on the interface stability. The study presents the competing effects of mechanical and electrical overpotential on the reaction distribution, and demarcates the regimes under which stress interactions can be tailored to enable stable electrodeposition. It is revealed that different degrees of mechanics contribution to the forward (dissolution) and backward (deposition) reaction rates result in widely varying stability regimes, and the mechanics‐coupled kinetics scenario exhibited by the Li/SE interface is shown to depend strongly on the thermodynamic and mechanical properties of the SE. This work highlights the importance of discerning the underpinning nature of electro‐chemo‐mechanical coupling toward achieving stable solid/solid interfaces in SSBs. 
    more » « less
  2. ; ; ; (, Journal of Materials Chemistry A)
    Amorphous Li 3 PS 4 (LPS) solid-state electrolytes are promising for energy-dense lithium metal batteries. LPS glass, synthesized from a 3 : 1 mol ratio of Li 2 S and P 2 S 5 , has high ionic conductivity and can be synthesized by ball milling or solution processing. Ball milling has been attractive because it provides the easiest route to access amorphous LPS with a conductivity of 3.5 × 10 −4 S cm −1 (20 °C). However, achieving the complete reaction of precursors via ball milling can be difficult, and most literature reports use X-ray diffraction (XRD) or Raman spectroscopy to confirm sample purity, both of which have limitations. Furthermore, the effect of residual precursors on ionic conductivity and lithium metal cycling is unknown. In this work, we illustrate the importance of multimodal characterization to determine LPS phase and chemical purity. To determine the residual Li 2 S content in LPS, we show that (1) XRD and 31 P solid state nuclear magnetic resonance (ssNMR) are insufficient and (2) Raman loses sensitivity at concentrations below 12 mol% Li 2 S. Most importantly, we show that 7 Li ssNMR is highly sensitive. Using 7 Li ssNMR, we investigate the effect of ball milling parameters and develop a robust and highly reproducible procedure for pure LPS synthesis. We find that as the residual Li 2 S precursor content increases, LPS conductivity decreases and lithium metal batteries exhibit higher overpotentials and poor cycle life. Our work reveals the importance of multimodal characterization techniques for amorphous solid-state electrolyte characterization and will enable better synthetic strategies for highly conductive electrolytes for efficient energy-dense solid-state lithium metal batteries. 
    more » « less
  3. ; ; ; ; ; (, Advanced Energy Materials)
    Abstract The performance of all‐solid‐state batteries (ASSBs) relies on the Li+transport and stability characteristics of solid electrolytes (SEs). Li3PS4is notable for its stability against lithium metal, yet its ionic conductivity remains a limiting factor. This study leverages local structural disorder via O substitution to achieve an ionic conductivity of 1.38 mS cm−1with an activation energy of 0.34 eV for Li3PS4−xOx(x = 0.31). Optimal O substitution transforms Li+transport from 2D to 3D pathways with increased ion mobility. Li3PS3.69O0.31exhibits improvements in the critical current density and stability against Li metal and retains its electrochemical stability window compared with Li3PS4. The practical implementation of Li3PS3.69O0.31in ASSBs half‐cells, particularly when coupled with TiS2as the cathode active material, demonstrates substantially enhanced capacity and rate performance. This work elucidates the utility of introducing local structural disorder to ameliorate SE properties and highlights the benefits of strategically combining the inherent strengths of sulfides and oxides via creating oxysulfide SEs. 
    more » « less
  4. ; ; ; ; ; ; (, Advanced Materials)
    Abstract Lithium metal (Li0) solid‐state batteries encounter implementation challenges due to dendrite formation, side reactions, and movement of the electrode–electrolyte interface in cycling. Notably, voids and cracks formed during battery fabrication/operation are hot spots for failure. Here, a self‐healing, flowable yet solid electrolyte composed of mobile ceramic crystals embedded in a reconfigurable polymer network is reported. This electrolyte can auto‐repair voids and cracks through a two‐step self‐healing process that occurs at a fast rate of 5.6 µm h−1. A dynamical phase diagram is generated, showing the material can switch between liquid and solid forms in response to external strain rates. The flowability of the electrolyte allows it to accommodate the electrode volume change during Li0stripping. Simultaneously, the electrolyte maintains a solid form with high tensile strength (0.28 MPa), facilitating the regulation of mossy Li0deposition. The chemistries and kinetics are studied by operando synchrotron X‐ray and in situ transmission electron microscopy (TEM). Solid‐state NMR reveals a dual‐phase ion conduction pathway and rapid Li+diffusion through the stable polymer‐ceramic interphase. This designed electrolyte exhibits extended cycling life in Li0–Li0cells, reaching 12 000 h at 0.2 mA cm−2and 5000 h at 0.5 mA cm−2. Furthermore, owing to its high critical current density of 9 mA cm−2, the Li0–LiNi0.8Mn0.1Co0.1O2(NMC811) full cell demonstrates stable cycling at 5 mA cm−2for 1100 cycles, retaining 88% of its capacity, even under near‐zero stack pressure conditions. 
    more » « less
  5. ; ; ; (, Advanced Materials Interfaces)
    Abstract Gel polymer electrolytes (GPEs) have attracted considerable attention due to their advantageous properties, such as uniform lithium deposition, stable solid electrolyte interphase (SEI) formation, nontoxicity, nonflammability, and leak‐proof characteristics. In this study, a polyvinylidene fluoride hexafluoropropylene copolymer (PVDF‐HFP)‐based gel polymer electrolyte is synthesized via photo‐polymerization, with a focus on examining the effects of curing time on electrolyte performance. The findings reveal that UV irradiation conditions significantly influence key material and electrochemical properties of the GPEs, including lithium‐ion transference number, ionic conductivity, crystallinity, morphology, and liquid electrolyte uptake. Notably, the GPE cured for 120 s exhibited optimized performance, achieving an ionic conductivity of 1.10 mS cm−1at room temperature, an expanded electrochemical voltage window of 4.38 V, and a lithium‐ion transference number of 0.50. This optimized GPE enabled long‐term Li plating/stripping in a Li//Li symmetric cell and demonstrated stably cycling performance in both half‐cell and full‐cell configurations. Overall, this study highlights the critical role of crosslinking in regulating the electrochemical performance of GPEs and provides valuable insights for the development of high‐performance GPE‐based quasi‐solid‐state batteries. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email