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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Interfacial Defect of Lithium Metal in Solid-State Batteries

All-solid-state battery with Li metal anode is a promising rechargeable battery technology with high energy density and improved safety. Currently, the application of Li metal anode is plagued by the failure at the interfaces between lithium metal and solid electrolyte (SE). However, little is known about the defects at Li–SE interfaces and their effects on Li cycling, impeding further improvement of Li metal anodes. Herein, by performing large-scale atomistic modeling of Li metal interfaces with common SEs, we discover that lithium metal forms an interfacial defect layer of nanometer-thin disordered lithium at the Li–SE interfaces. Further, this interfacial defect Li layer is highly detrimental, leading to interfacial failure such as pore formation and contact loss during Li stripping. By systematically studying and comparing incoherent, coherent, and semi-coherent Li–SE interfaces, we find that the interface with good lattice coherence has reduced Li defects at the interface and has suppressed interfacial failure during Li cycling. Our finding discovered the critical roles of atomistic lithium defects at interfaces for the interfacial failure of Li metal anode, and motivates future atomistic-level interfacial engineering for Li metal anode in solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2023

Lithium crystallization at solid interfaces

Understanding the electrochemical deposition of metal anodes is critical for high-energy rechargeable batteries, among which solid-state lithium metal batteries have attracted extensive interest. A long-standing open question is how electrochemically deposited lithium-ions at the interfaces with the solid-electrolytes crystalize into lithium metal. Here, using large-scale molecular dynamics simulations, we study and reveal the atomistic pathways and energy barriers of lithium crystallization at the solid interfaces. In contrast to the conventional understanding, lithium crystallization takes multi-step pathways mediated by interfacial lithium atoms with disordered and random-closed-packed configurations as intermediate steps, which give rise to the energy barrier of crystallization. This understanding of multi-step crystallization pathways extends the applicability of Ostwald’s step rule to interfacial atom states, and enables a rational strategy for lower-barrier crystallization by promoting favorable interfacial atom states as intermediate steps through interfacial engineering. Our findings open rationally guided avenues of interfacial engineering for facilitating the crystallization in metal electrodes for solid-state batteries and can be generally applicable for fast crystal growth.

25 ENERGY STORAGE↗
DOE OSTI2024

Self‐Templated 3D Sulfide‐Based Solid Composite Electrolyte for Solid‐State Sodium Metal Batteries

Abstract Rechargeable solid‐state sodium metal batteries (SSMBs) experience growing attention owing to the increased energy density (vs Na‐ion batteries) and cost‐effective materials. Inorganic sulfide‐based Na‐ion conductors also possess significant potential as promising solid electrolytes (SEs) in SSMBs. Nevertheless, due to the highly reactive Na metal, poor interface compatibility is the biggest obstacle for inorganic sulfide solid electrolytes such as Na 3 SbS 4 to achieve high performance in SSMBs. To address such electrochemical instability at the interface, new design of sulfide SE nanostructures and interface engineering are highly essential. In this work, a facile and straightforward approach is reported to prepare 3D sulfide‐based solid composite electrolytes (SCEs), which utilize porous Na 3 SbS 4 (NSS) as a self‐templated framework and fill with a phase transition polymer. The 3D structured SCEs display obviously improved interface stability toward Na metal than pristine sulfide. The assembled SSMBs (with TiS 2 or FeS 2 as cathodes) deliver outstanding electrochemical cycling performance. Moreover, the cycling of high‐voltage oxide cathode Na 0.67 Ni 0.33 Mn 0.67 O 2 (NNMO) is also demonstrated in SSMBs using 3D sulfide‐based SCEs. This study presents a novel design on the self‐templated nanostructure of SCEs, paving the way for the advancement of high‐energy sodium metal batteries.

Guo, Xiaolin↗
DOE OSTI2020

Elucidating Interfacial Stability between Lithium Metal Anode and Li Phosphorus Oxynitride via In Situ Electron Microscopy

Li phosphorus oxynitride (LiPON) is one of a very few solid electrolytes that have demonstrated high stability against Li metal and extended cyclability with high Coulombic efficiency for all solid-state batteries (ASSBs). However, theoretical calculations show that LiPON reacts with Li metal. Here, we utilize in situ electron microscopy to observe the dynamic evolutions at the LiPON–Li interface upon contacting and under biasing. We reveal that a thin interface layer (~60 nm) develops at the LiPON–Li interface upon contact. This layer is composed of conductive binary compounds that show a unique spatial distribution that warrants an electrochemical stability of the interface, serving as an effective passivation layer. Our results explicate the excellent cyclability of LiPON and reconcile the existing debates regarding the stability of the LiPON–Li interface, demonstrating that, though glassy solid electrolytes may not have a perfect initial electrochemical window with Li metal, they may excel in future applications for ASSBs.

25 ENERGY STORAGE↗
DOE OSTI2024

The Impact of Lithium Anode Interface on Capacity Fade in Polymer Electrolyte-Based Solid-State Batteries

This study investigates the Li stripping-plating morphology and failure mechanisms in full cells consisting of a solid polymer electrolyte (SPE) with two commercial Li anodes: Li chip and Li foil. The primary identified failure mechanism of the SPE cell is capacity fade, regardless of the Li manufacturer. While the cathode’s role in capacity fade is evident, the Li anode significantly influences cycling performance, with Li foil cells cycling 50% longer than Li chip cells, a statistical difference. Further, post-mortem scanning electron microscopy and X-ray photoelectron spectroscopy results attribute the Li chip’s faster capacity fade to a loss of contact and continuous growth of the solid electrolyte interphase (SEI). Conversely, Li foil maintains consistent contact with the solid polymer, displaying a thin and stable SEI. Additionally, failure mechanisms between a gel electrolyte in previous work and the dry SPE are compared.

25 ENERGY STORAGE↗
DOE OSTI2021

A Morphologically Stable Li/Electrolyte Interface for All-Solid-State Batteries Enabled by 3D-Micropatterned Garnet

Morphological degradation at the Li/solid-state electrolyte (SSE) interface is a prevalent issue causing performance fading of all-solid-state batteries (ASSBs). To maintain the interfacial integrity, most ASSBs are operated under low current density with considerable stack pressure, which significantly limits their widespread usage. In this work, a novel 3D-micropatterned SSE (3D-SSE) that can stabilize the morphology of the Li/SSE interface even under relatively high current density and limited stack pressure is reported. Under the pressure of 1.0 MPa, the Li symmetric cell using a garnet-type 3D-SSE fabricated by laser machining shows a high critical current density of 0.7 mA cm –2 and stable cycling over 500 h under 0.5 mA cm –2 . This excellent performance is attributed to the reduced local current density and amplified mechanical stress at the Li/3D-SSE interface. These two effects can benefit the flux balance between Li stripping and creep at the interface, thereby pre-venting interfacial degradation such as void formation and dendrite growth.

3D-micropatterned garnet↗
DOE OSTI2019

Stabilizing the Interface between Sodium Metal Anode and Sulfide-Based Solid-State Electrolyte with an Electron-Blocking Interlayer

Sulfide-based Na-ion conductors are promising electrolytes for all-solid-state sodium batteries (ASSSBs) because of high ionic conductivity and favorable formability. However, no effective strategy has been reported for long-duration Na cycling with sulfide-based electrolytes because of interfacial challenges. Here we demonstrate that a cellulose–poly(ethylene oxide) (CPEO) interlayer can stabilize the interface between sulfide electrolyte (Na 3 SbS 4 ) and Na by shutting off the electron pathway of the electrolyte decomposition reaction. In conclusion, we achieved stable Na plating/stripping for 800 cycles at 0.1 mA cm –2 in all-solid-state devices at 60 °C.

25 ENERGY STORAGE↗
DOE OSTI2018

An Electron/Ion Dual‐Conductive Alloy Framework for High‐Rate and High‐Capacity Solid‐State Lithium‐Metal Batteries

Abstract The solid‐state Li battery is a promising energy‐storage system that is both safe and features a high energy density. A main obstacle to its application is the poor interface contact between the solid electrodes and the ceramic electrolyte. Surface treatment methods have been proposed to improve the interface of the ceramic electrolytes, but they are generally limited to low‐capacity or short‐term cycling. Herein, an electron/ion dual‐conductive solid framework is proposed by partially dealloying the Li–Mg alloy anode on a garnet‐type solid‐state electrolyte. The Li–Mg alloy framework serves as a solid electron/ion dual‐conductive Li host during cell cycling, in which the Li metal can cycle as a Li‐rich or Li‐deficient alloy anode, free from interface deterioration or volume collapse. Thus, the capacity, current density, and cycle life of the solid Li anode are improved. The cycle capability of this solid anode is demonstrated by cycling for 500 h at 1 mA cm −2 , followed by another 500 h at 2 mA cm −2 without short‐circuiting, realizing a record high cumulative capacity of 750 mA h cm −2 for garnet‐type all‐solid‐state Li batteries. This alloy framework with electron/ion dual‐conductive pathways creates the possibility to realize high‐energy solid‐state Li batteries with extended lifespans.

Yang, Chunpeng↗
DOE OSTI2020

Electro-chemo-mechanical evolution of sulfide solid electrolyte/Li metal interfaces: operando analysis and ALD interlayer effects

Sulfide solid electrolytes (SE) show promise for high-performance solid-state batteries because of their high ionic conductivity and ease of processing. However, sulfide electrolytes have suffered from chemical and electrochemical instability against Li metal anodes. In this paper, we use a suite of in situ/operando microscopy and spectroscopy techniques to demonstrate that Al 2 O 3 interlayers deposited using atomic layer deposition (ALD) delay degradation at the Li/LGPS interface by modifying the solid electrolyte interphase (SEI) chemistry and morphology. Optical and scanning electron microscopy are used to rationalize the electrochemical response of the system, which is attributed to a delayed onset of mechanical degradation at the interface when ALD interlayers are used. Operando X-ray photoelectron spectroscopy demonstrates that the dynamic evolution of SEI chemistry is impacted by the presence of the ALD interlayer. In situ Auger spectroscopy and operando optical microscopy provide visual evidence of spatial heterogeneity of Li plating, which is attributed to the chemo-mechanical degradation of the ALD interphase. The implications of these observations provide valuable insights toward the development of robust interlayers for solid-state batteries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Locally Confined Polysulfide-Reactive Electrolytes for Shuttle-Free Sodium–Sulfur Batteries

Sodium-sulfur batteries promise high-energy-density and sustainable electrochemical energy storage but suffer from uncontrolled polysulfides dissolution and high sodium reactivity. These challenges fundamentally originate from poor electrolyte-electrode compatibility. Current electrolyte research inadequately addresses the trade-off between minimal polysulfides solvation and stabilizing sodium interfaces. Here, we present a locally-confined polysulfide-reactive electrolyte strategy that mediates the polysulfide dissolution dynamics and sodium stability by leveraging an electrophilic solvating species with a localized high-concentration electrolyte. This design enables shuttle-free cell operation by synergistically restricting the global solvating power of the electrolyte through intermolecular interactions and locally scavenging sparingly dissolved polysulfides via electrolyte electrophilicity. The precisely confined surface reaction facilitates a protective cathode-electrolyte interface, realizing a quasi-solid-state sulfur conversion in our liquid ether-based electrolyte, which crucially avoids crossover-induced catastrophic sodium-metal degradation. The proposed electrolyte demonstrates long-term cycling of high-mass-loading sulfur cathodes (> 3 mg S cm −2 with commercial carbon host and 70 wt% sulfur content), which afford 710 mA h g −1 over 400 cycles in coin cells and steady pouch cell operation over 180 cycles. Furthermore, this work establishes a scalable electrolyte design protocol that regulates the reaction chemistry of highly reactive electrodes, offering a pathway toward sustainable renewable energy storage.

25 ENERGY STORAGE↗
DOE OSTI2021

Chemical Heterogeneity in PAN/LLZTO Composite Electrolytes by Synchrotron Imaging

Solid polymer/ceramic composite electrolytes are promising for batteries due to their attractive thermal stability and mechanical properties. Chemical heterogeneity in solid composite electrolytes, such as the inhomogeneity in the ceramic phase and salt distribution at the polymer/ceramic interface, is critical to the performance of solid composite electrolytes. However, such heterogeneity has not been well understood yet. In this work, we use Synchrotron-based X-ray fluorescence imaging (XRF) and Transmission X-ray Microscope (TXM) to image nanoscale chemical heterogeneity in polyacrylamide/Li 7+x La 3 Zr 2–x Ta x O 12 (LLZTO) composite electrolytes and investigate the effects of lithium salt, salt concentration, and plasticizer. We find that LLZTO particles show strong inter- and intra-particles chemical heterogeneities, and the off-stoichiometry of Zr in an LLZTO particle is unlikely to be only balanced by Ta substitution. Moreover, statistical analysis suggests that LiI tends to accumulate at the ceramic/polymer interface at a low concentration of 5 wt%, but no such tendency was observed in samples with 10 wt% LiI. However, composite electrolytes with LiTFSI show interfacial accumulation at both 5 wt% and 10 wt%. Furthermore, this report provides insight into element distributions in solid composite electrolytes, and we hope further researches can shed light on the connections between chemical heterogeneity and ionic transport pathway inside.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Probing electrolyte–silica interactions through simulations of the infrared spectroscopy of nanoscale pores

The structural and dynamical properties of nanoconfined solutions can differ dramatically from those of the corresponding bulk systems. Understanding the changes induced by confinement is central to controlling the behavior of synthetic nanostructured materials and predicting the characteristics of biological and geochemical systems. A key outstanding issue is how the molecular-level behavior of nanoconfined electrolyte solutions is reflected in different experimental, particularly spectroscopic, measurements. This is addressed here through molecular dynamics simulations of the OH stretching infrared (IR) spectroscopy of NaCl, NaBr, and NaI solutions in isotopically dilute HOD/D 2 O confined in hydroxylated amorphous silica slit pores of width 1–6 nm and pH ~2. In addition, the water reorientation dynamics and spectral diffusion, accessible by pump–probe anisotropy and two-dimensional IR measurements, are investigated. In this work, the aim is to elucidate the effect of salt identity, confinement, and salt concentration on the vibrational spectra. It is found that the IR spectra of the electrolyte solutions are only modestly blue-shifted upon confinement in amorphous silica slit pores, with both the size of the shift and linewidth increasing with the halide size, but these effects are suppressed as the salt concentration is increased. This indicates the limitations of linear IR spectroscopy as a probe of confined water. However, the OH reorientational and spectral diffusion dynamics are significantly slowed by confinement even at the lowest concentrations. The retardation of the dynamics eases with increasing salt concentration and pore width, but it exhibits a more complex behavior as a function of halide.

Mesoporous material↗
DOE OSTI2022

Long–Cycling Sulfide–Based All–Solid–State Batteries Enabled by Electrochemo–Mechanically Stable Electrodes

Anode significantly determines the energy density of all-solid-state Lithium batteries (ASLBs). Silicon (Si) and Lithium (Li) metal are two of the most attractive anodes because of their ultrahigh theoretical capacities. However, most investigations focus on Li metal; the great potential of Si is underrated. This study investigates Si anode's stability, processability, and cost in ASLBs and compares them with Li metal. Moreover, the single-crystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 is stabilized with a lithium silicate (Li 2 SiO x ) through a scalable sol-gel method. ASLBs with a cell-level energy density of 285 Wh kg -1 are obtained through sandwiching Si anode, thin sulfide solid-state electrolyte membrane, and interface stabilized LiNi 0.8 Co 0.1 Mn 0.1 O 2 . The full cell delivered a high capacity of 145 mAh g -1 at C/3 and maintained stability for 1000 cycles. This work inspires commercializing the ASLBs on a large scale with exciting manufacturing lines for large-scale, safe, and economical energy storage.

25 ENERGY STORAGE↗
DOE OSTI2018

Garnet Electrolyte Surface Degradation and Recovery

Ceramic materials based on the garnet structure Li 7 La 3 Zr 2 O 12 (LLZO) show great promise as lithium-ion conducting electrolytes for solid-state lithium batteries. However, these materials exhibit surface degradation when exposed to air and moisture, which adversely impacts their functioning in operating devices. In this work, we use several depth-profiling and in situ techniques to probe the nature of the surface reactions that occur when aluminum (Al)-substituted LLZO is exposed to air. These experiments show that a proton exchange reaction occurs near the surface of the LLZO and leads to change in its chemistry and structure, concomitant with the formation of Li 2 CO 3 . But these reactions can be readily reversed by heating samples at 250 °C under an inert atmosphere to recover LLZO surface chemistry and structure. Symmetrical cells containing samples treated this way exhibited much lower area specific impedances than those containing air-exposed LLZO without the treatment, confirming the reversal of the degradation process. Finally, our results show a process to rejuvenate LLZO surface, and this opens the possibility of integrating this material in solid-state devices.

25 ENERGY STORAGE↗
DOE OSTI2026

Unveiling the High‐Voltage Reactivity and Gas Evolution With Aluminum‐Based Chloride and Oxychloride Catholytes in Solid‐State Sodium Batteries

All-solid-state sodium batteries (ASSBs) employing halide solid electrolytes (SEs) offer a cost-effective and energy-dense alternative to conventional liquid electrolyte systems. However, their high voltage (>4 V vs. Na/Na + ) performance remains limited by interfacial instability between the cathode active material (CAM) and the SE. We present here the electrochemical and interfacial behaviors of crystalline NaAlCl 4 and amorphous sodium–aluminum–oxychloride (NACO) SEs when combined with NaNi 0.5 Mn 0.5 O 2 cathode. While oxygen incorporation in NACO enhances ionic conductivity by nearly three orders of magnitude relative to NaAlCl 4 , it does not improve high-voltage cycling stability. Cells employing NACO exhibit accelerated capacity fade, increased cell impedance growth, and intrinsic oxygen evolution above 4.5 V vs. Na 3 Sn, as revealed by operando electrochemical mass spectrometry. In contrast, the NaAlCl 4 -based cells show no detectable gas release, underscoring their superior high-voltage stability and safety. Time-of-flight secondary-ion mass spectrometry confirms the formation of Al─O and Ni/Mn─Cl species, respectively, in the SE and CAM, indicating redox-driven anion exchange that contributes to kinetic hindrance of high-voltage phase transitions. The findings establish that while oxygen incorporation enhances ionic transport, it can compromise interfacial stability, suggesting pure chloride SEs may offer a more robust and intrinsically safer pathway for developing high-energy ASSBs.

25 ENERGY STORAGE↗
DOE OSTI2024

Deconvoluting Effects of Lithium Morphology and SEI Stability at Moderate Current Density Using Interface Engineering

Lithium (Li)-morphology and solid electrolyte interphase (SEI) are among the most significant performance regulators in Li-metal batteries (LMBs). While both Li-morphology and SEI composition play key roles in the cyclability of LMBs, less is understood about the individual contributions of each factor to overall Li reversibility, particularly at a practical current density (1 mA cm −2 ) at which the kinetics of both factors are not naturally separated. Herein, an interface engineering approach is introduced to deconvolute the impacts of Li-morphology and SEI composition on battery performance. By using interfacial nanofilms with differing resistivity (resistive HfO 2 versus conductive ZnO), the morphology of Li is varied, and by virtue of similar acidic character of the nanofilms, the formation of anion-rich SEIs is maintained. It is established that although the surface acidity of the thin films enables preformation of a more anion-rich SEI, it is not preserved after Li plating. It is further shown that resistance-controlled, low-surface-area Li-morphology exhibits up to threefold increase in stable cycle life when tested in multiple electrolytes. Overall, these findings explain why Li-morphological control is more advantageous for performance improvement than preformed SEI modulation due to the inherent challenges in SEI preservation.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Intermetallics Based on Sodium Chalcogenides Promote Stable Electrodeposition–Electrodissolution of Sodium Metal Anodes

Sodiophilic micro-composite films of sodium-chalcogenide intermetallics (Na 2 Te and Na 2 S) and Cu particles are fabricated onto commercial copper foam current collectors (Na 2 Te@CF and Na 2 S@CF). For the first time a controllable capacity thermal infusion process is demonstrated. Enhanced wetting by the metal electrodeposition leads to state-of-the-art electrochemical performance. For example, Na 2 Te@CF-based half-cells demonstrate stable cycling at 6 mA cm -2 and 6 mAh cm -2 , corresponding to 54 µm of Na electrodeposited/electrodissolved by geometric area. Sodium metal batteries with Na 3 V 2 (PO 4 ) 3 cathodes are stable at 30C (7 mA cm -2 ) and for 10 000 cycles at 5C and 10C. Cross-sectional cryogenic focused ion beam (cryo-FIB) microscopy details deposited and remnant dissolved microstructures. Sodium metal electrodeposition onto Na 2 Te@CF is dense, smooth, and free of dendrites or pores. On unmodified copper foam, sodium grows in a filament-like manner, not requiring cycling to achieve this geometry. Substrate–metal interaction critically affects the metal–electrolyte interface, namely the thickness and morphology of the solid electrolyte interphase. Density functional theory and mesoscale simulations provide insight into support-adatom energetics, nucleation response, and early-stage morphological evolution. On Na 2 Te sodium atomic dispersion is thermodynamically more stable than isolated clusters, leading to conformal adatom coverage of the surface.

36 MATERIALS SCIENCE↗