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At least 397 records · Page 22

Chemical interaction and enhanced interfacial ion transport in a ceramic nanofiber–polymer composite electrolyte for all-solid-state lithium metal batteries

This article reports the synergy between ceramic nanofibers and a polymer, and the enhanced interfacial Li-ion transport along the nanofiber/polymer interface in a solid-state ceramic/polymer composite electrolyte, in which a three-dimensional (3D) electrospun aluminum-doped Li 0.33 La 0.557 TiO 3 (LLTO) nanofiber network is embedded in a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) matrix. Strong chemical interaction occurs between the nanofibers and the polymer matrix. Addition of the ceramic nanofibers into the polymer matrix results in the dehydrofluorination of the PVDF chains, deprotonation of the –CH 2 moiety and amorphization of the polymer matrix. Solid-state nuclear magnetic resonance (NMR) spectra reveal that lithium ions transport via three pathways: (i) intra-polymer transport, (ii) intra-nanofiber transport, and (iii) interfacial polymer/nanofiber transport. In addition, lithium phosphate is coated on the LLTO nanofiber surface before the nanofibers are embedded into the polymer matrix. The presence of lithium phosphate at the LLTO/polymer interface further enhances the chemical interaction between the nanofibers and the polymer, which promotes the lithium ion transport along the polymer/nanofiber interface. This in turn improves the ionic conductivity and electrochemical cycling stability of the nanofiber/polymer composite. As a result, the flexible LLTO/Li 3 PO 4 /polymer composite electrolyte membrane exhibits an ionic conductivity of 5.1 × 10 -4 S cm -1 at room temperature and an electrochemical stability window of 5.0 V vs. Li/Li + . A symmetric Li|electrolyte|Li half-cell shows a low overpotential of 50 mV at a constant current density of 0.5 mA cm -2 for more than 800 h. In addition, a full cell is constructed by sandwiching the composite electrolyte between a lithium metal anode and a LiFePO 4 -based cathode. Such an all-solid-state lithium metal battery exhibits excellent cycling performance and rate capability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Synthesis of Fluorine-Doped Lithium Argyrodite Solid Electrolytes for Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) that utilize novel solid electrolytes (SEs) have garnered much attention because of their potential to yield safe and high-energy-density batteries. Sulfide-based argyrodite-class SEs are an attractive option because of their impressive ionic conductivity. Recent studies have shown that LiF at the interface between Li and SE enhances electrochemical stability. However, the synthesis of F-doped argyrodites has remained challenging because of the high temperatures used in the state-of-the-art solid-state synthesis methods. In this work, for the f irst time, we report F-doped Li 5+y PS 5 F y argyrodites with a tunable doping content and dual dopants (F-/Cl- and F-/Br-) that were synthesized through a solvent-based approach. Among all compositions, Li 6 PS 5 F 0.5 C l0.5 exhibits the highest Li-ion conductivity of 3.5 x 10 -4 S cm -1 at room temperature (RT). Furthermore, Li symmetric cells using Li 6 PS 5 F 0.5 Cl 0.5 show the best cycling performance among the tested cells. X-ray photoelectron spectroscopy and ab initio molecular dynamics simulations revealed that the enhanced interfacial stability of Li 6 PS 5 F 0.5 C l0.5 SE against Li metal can be attributed to the formation of a stable solid electrolyte interphase (SEI)-containing conductive species (Li 3 P), alongside LiCl and LiF. These findings open new opportunities to develop high-performance SSLMBs using a novel class of F-doped argyrodite electrolytes.

25 ENERGY STORAGE↗

High‐Entropy Lithium Argyrodite Solid Electrolytes Enabling Stable All‐Solid‐State Batteries

Abstract Superionic solid electrolytes (SEs) are essential for bulk‐type solid‐state battery (SSB) applications. Multicomponent SEs are recently attracting attention for their favorable charge‐transport properties, however a thorough understanding of how configurational entropy (ΔS conf ) affects ionic conductivity is lacking. Here, we successfully synthesized a series of halogen‐rich lithium argyrodites with the general formula Li 5.5 PS 4.5 Cl x Br 1.5‐x (0≤x≤1.5). Using neutron powder diffraction and 31 P magic‐angle spinning nuclear magnetic resonance spectroscopy, the S 2− /Cl − /Br − occupancy on the anion sublattice was quantitatively analyzed. We show that disorder positively affects Li‐ion dynamics, leading to a room‐temperature ionic conductivity of 22.7 mS cm −1 (9.6 mS cm −1 in cold‐pressed state) for Li 5.5 PS 4.5 Cl 0.8 Br 0.7 (ΔS conf =1.98R). To the best of our knowledge, this is the first experimental evidence that configurational entropy of the anion sublattice correlates with ion mobility. Our results indicate the possibility of improving ionic conductivity in ceramic ion conductors by tailoring the degree of compositional complexity. Moreover, the Li 5.5 PS 4.5 Cl 0.8 Br 0.7 SE allowed for stable cycling of single‐crystal LiNi 0.9 Co 0.06 Mn 0.04 O 2 (s‐NCM90) composite cathodes in SSB cells, emphasizing that dual‐substituted lithium argyrodites hold great promise in enabling high‐performance electrochemical energy storage.

Chemistry↗

Encapsulated sulfide glass solid electrolytes and solid-state laminate electrode assemblies

Nanofilm-encapsulated sulfide glass solid electrolyte structures and methods for making the encapsulated glass structures involve a lithium ion conducting sulfide glass sheet encapsulated on its opposing major surfaces by a continuous and conformal nanofilm made by atomic layer deposition (ALD). During manufacture, the reactive surfaces of the sulfide glass sheet are protected from deleterious reaction with ambient moisture, and the nanofilm can be configured to provide additional performance advantages, including enhanced mechanical strength and improved chemical resistance.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Encapsulated sulfide glass solid electrolytes and solid-state laminate electrode assemblies

Nanofilm-encapsulated sulfide glass solid electrolyte structures and methods for making the encapsulated glass structures involve a lithium ion conducting sulfide glass sheet encapsulated on its opposing major surfaces by a continuous and conformal nanofilm made by atomic layer deposition (ALD). During manufacture, the reactive surfaces of the sulfide glass sheet are protected from deleterious reaction with ambient moisture, and the nanofilm can be configured to provide additional performance advantages, including enhanced mechanical strength and improved chemical resistance.

Visco, Steven J.↗

Encapsulated sulfide glass solid electrolytes and solid-state laminate electrode assemblies

Nanofilm-encapsulated sulfide glass solid electrolyte structures and methods for making the encapsulated glass structures involve a lithium ion conducting sulfide glass sheet encapsulated on its opposing major surfaces by a continuous and conformal nanofilm made by atomic layer deposition (ALD). During manufacture, the reactive surfaces of the sulfide glass sheet are protected from deleterious reaction with ambient moisture, and the nanofilm can be configured to provide additional performance advantages, including enhanced mechanical strength and improved chemical resistance.

Visco, Steven J.↗

An electrochemically stable homogeneous glassy electrolyte formed at room temperature for all-solid-state sodium batteries

All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na 3 PS 4-x O x , where 0 < x ≤ 60) that not only exhibit the highest critical current density among all Na-ion conducting sulfide-based SEs, but also enable high-performance ambient-temperature sodium-sulfur batteries. By forming bridging oxygen units, the Na 3 PS 4-x Ox SEs undergo pressure-induced sintering at room temperature, resulting in a fully homogeneous glass structure with robust mechanical properties. Furthermore, the self-passivating solid electrolyte interphase at the Na|SE interface is critical for interface stabilization and reversible Na plating and stripping. The new structural and compositional design strategies presented here provide a new paradigm in the development of safe, low-cost, energy-dense, and long-lifetime ASSSBs.

25 ENERGY STORAGE↗

Investigation of MgO additives on microstructure and properties of thin LLZO electrolytes for all-solid-state batteries

To realize high-energy density lithium lanthanum zirconate (LLZO)-based solid-state batteries (SSB), LLZO electrolytes should be fabricated with low thickness and high mechanical strength. An effective strategy for strengthening ceramic materials is to use additives. Here, we employed MgO nanopowders and fibers as additives for the thin LLZO electrolyte in order to improve the mechanical strength. The microstructure, mechanical properties, and electrochemical properties are characterized to investigate the effects of adding MgO and sintering time. The MgO remains at grain boundaries after sintering, making the microstructure of LLZO fine and uniform. The mechanical strength of the MgO-added LLZO was enhanced by more than 60% while maintaining high ionic conductivity (1 × 10 -4 S cm -1 ) at room temperature. Li symmetric cells using the MgO fiber–LLZO and MgO powder–LLZO exhibit 2 and 3 times higher critical current density (CCD) than those of pure LLZO, and a solid-state full cell exhibits stable cycling performance. Further, these results demonstrate that the use of MgO nanopowder or fiber as an additive for thin LLZO is beneficial for high-current density cycling, by improving mechanical properties and microstructure.

25 ENERGY STORAGE↗

Formation of Stable Interphase of Polymer-in-Salt Electrolyte in All-Solid-State Lithium Batteries

The integration of solid-polymer electrolytes into all-solid-state lithium batteries is highly desirable to overcome the limitations of current battery configurations that have a low energy density and severe safety concerns. Polyacrylonitrile is an appealing matrix for solid-polymer electrolytes; however, the practical utilization of such polymer electrolytes in all-solid-state cells is impeded by inferior ionic conductivity and instability against a lithium-metal anode. In this work, we show that a polymer-in-salt electrolyte based on polyacrylonitrile with a lithium salt as the major component exhibits a wide electrochemically stable window, a high ionic conductivity, and an increased lithium-ion transference number. The growth of dendrites from the lithium-metal anode was suppressed effectively by the polymer-in-salt electrolyte to increase the safety features of the batteries. In addition, we found that a stable interphase was formed between the lithium-metal anode and the polymer-in-salt electrolyte to restrain the uncontrolled parasitic reactions, and we demonstrated an all-solid-state battery configuration with a LiFePO 4 cathode and the polymer-in-salt electrolyte, which exhibited a superior cycling stability and rate capability.

Gao, Hongcai↗

Li 2 S 6 ‐Integrated PEO‐Based Polymer Electrolytes for All‐Solid‐State Lithium‐Metal Batteries

Abstract The integration of Li 2 S 6 within a poly(ethylene oxide) (PEO)‐based polymer electrolyte is demonstrated to improve the polymer electrolyte's ionic conductivity because the strong interplay between O 2− (PEO) and Li + from Li 2 S 6 reduces the crystalline volume within the PEO. The Li/electrolyte interface is stabilized by the in situ formation of an ultra‐thin Li 2 S/Li 2 S 2 layer via the reaction between Li 2 S 6 and lithium metal, which increases the ionic transport at the interface and suppresses lithium dendrite growth. A symmetric Li/Li cell with the Li 2 S 6 ‐integrated composite electrolyte has excellent cyclability and a high critical current density of 0.9 mA cm −2 at 40 °C. Impressive electrochemical performance is demonstrated with all‐solid‐state Li/LiFePO 4 and high‐voltage Li/LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells at 40 °C.

Fang, Ruyi↗

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↗

Identifying Bounds of Inorganic Content in Solventless Processing of Hybrid Solid Electrolytes

Solid-state lithium batteries require safe, robust electrolytes to enable higher energy densities and improved safety over conventional cells. Hybrid polymer–ceramic electrolytes are a promising solution, combining the processability of polymers with the high ionic conductivity and mechanical strength of inorganic fillers. In this work, we demonstrate a solventless, UV-curing method to produce hybrid solid electrolytes using a poly(ethylene glycol) dimethyl ether (PEGDME)-based photocurable matrix incorporating Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) or Li 7 La 3 Zr 2 O 12 (LLZO) ceramic electrolyte. Inorganic filler loadings up to ∼55 wt.% could be successfully incorporated via this process which was the highest inorganic content at which the slurry remains processable and cured into a uniform film. The resulting UV-cured composite electrolytes remain flexible and exhibit room-temperature ionic conductivities on the order of 10 −4 S·cm −1 , along with notably improved lithium-ion transference numbers compared to conventional polymer electrolytes. Similar performance and processing limits were observed for both LAGP and LLZO, indicating that ceramic filler chemistry does not significantly affect the UV-curing process or the electrolyte's ion transport properties in this regime. Eliminating solvents from fabrication not only simplifies processing and mitigates environmental concerns but also enables higher solid contents that enhance mechanical strength and help suppress lithium dendrite formation. In conclusion, this scalable approach thus paves the way for manufacturing robust composite solid electrolytes for next-generation solid-state batteries (SSBs).

Batteries↗

Current Status and Future Directions of All-Solid-State Batteries with Lithium Metal Anodes, Sulfide Electrolytes, and Layered Ternary Oxide Cathodes

All-solid-state batteries (ASSBs) offer great promise as a next-generation energy storage technology with higher energy density, wider operating temperature range, and improved safety for electric vehicles. ASSBs employing lithium metal anodes (Li), sulfide-based solid-state electrolytes (SSE), and Ni-rich layered transition metal oxide cathodes (LiMO 2 , M = Ni, Mn, Co, Al) are particularly promising due to its superior electrochemical performance compared to other solid-electrolyte systems. However, the battery cycle life at high cathode mass loading and high current is still limited because the failure mechanism is not fully understood. Lithium dendrite growth at the anode or inside a solid electrolyte still represents as a serious risk of cell failure. Interfacial resistance increases attributed to electrolyte decomposition and interfacial void formation at both cathode–electrolyte and anode–electrolyte interfaces lead to gradual capacity fading. In this Review, we present the fundamental challenges and recent scientific understandings of each component in ASSBs. The novel diagnostic tools for these components, especially the interfaces buried under the surface that are often hard for characterization are mainly examined. Lastly, we offer a perspective for future research directions. We hope this Review will provide a timely snapshot of state-of-the-art research progress in ASSBs to accelerate the development of ASSBs.

25 ENERGY STORAGE↗

Single-Ion Conducting Polymer Electrolytes for Solid-State Lithium–Metal Batteries: Design, Performance, and Challenges

Realizing solid-state lithium batteries with higher energy density and enhanced safety compared to the conventional liquid lithium-ion batteries is one of the primary research and development goals set for next-generation batteries in this decade. In this regard, polymer electrolytes have been widely researched as solid electrolytes due to their excellent processability, flexibility, and low weight. With high cationic transference numbers (t Li + close to 1), single-ion conducting polymer electrolytes (SICPEs) have tremendous advantages compared to polymer electrolyte systems (t Li + < 0.4) because of their potential to reduce the buildup of ion concentration gradients and suppress growth of lithium dendrites. The current review covers the fundamentals of SICPEs, including anionic unit synthesis, polymer structure design, and film fabrication, along with simulation and experimental results in solid-state lithium–metal battery applications. Overall, a perspective on current challenges, possible solutions, and potential research directions of SICPEs is also discussed to provide the research community with the critical technical aspects that may advance SICPEs as solid electrolytes in next-generation energy storage systems.

25 ENERGY STORAGE↗

Solvent-Free and Non-Sintered 500 Wh/kg All Solid-State Battery

Navitas teamed up with UMD and ORNL to establish a reliable scientific research team. The project addressed processing limitations of state-of-the-art solid electrolytes by extending solvent-free electrode fabrication technology to the scalable production of cathode/solid electrolyte laminates. The innovation started with a solid-state sulfide electrolyte (LiPS) with Cl stabilization able to meet the keystone conductivity challenge in a film of practical thickness (μ 50 µm). The electrolyte was based on a composite of PTFE, and stabilized LiPSCl. With optimization, the ionic conductivity reached 3.3 ×10 -3 S/cm. The solid electrolyte with as low as 0.4% binder allowed long term cycling (> 500 cycles) of Li/SSE/Li cell at > 4 mA/cm 2 with the utilization of Li > 80%. The Li and SSE interfaces were successfully protected with LiF-rich SEI layer. NCM811cathode active materials were coated with a thin layer of Al 2 O 3 (5 nm). The free standing cathode film was fabricated through dry-process with Al2O3-coated NCM811, LiPSCl, active carbon, and small amount PTFE. The all-solid-state batteries were laminated with free standing surface coated NCM811 cathode film, free standing LiPSCl SSE film, and surface protected Li anode together in a single lamination step, and demonstrated high specific capacity (> 200 mAh/g) with coulombic efficiency > 99.5%. The all-solid-state batteries through solvent-free and no-sintering process are promising for large format cell with 500 Wh/Kg specific energy density.

25 ENERGY STORAGE↗

Interlayer Design for Halide Electrolytes in All‐Solid‐State Lithium Metal Batteries

Abstract All‐solid‐state lithium‐metal batteries (ASSLMBs) are promising for transportation electrification due to their superior safety and high energy density. Lithium halide electrolytes provide excellent processing flexibility, high ionic conductivity, and anodic stability (>4.1 V), making them highly compatible with high‐voltage cathodes, surpassing sulfide electrolytes (<2.1 V). Nevertheless, halide electrolytes suffer from low cathodic stability and form an electronically conductive interphase with lithium, resulting in a critical current density (CCD) of nearly zero. Herein, Li 3 YbCl 6 electrolytes are synthesized that are kinetically stable with lithium by forming an electronic insulating solid electrolyte interphase. Guided by critical overpotential criteria, a PI 3 interlayer is designed that transforms into Li 6 PI 3 upon contact with lithium, substantially reducing the interfacial resistance of Li 3 YbCl 6 against lithium to 34 Ω and achieving a high critical overpotential of 114 mV. By substituting Yb with Lu, Li 3 LuCl 6 electrolytes with Li 6 PI 3 interlayers reach a CCD of 1.0 mA cm −2 at a capacity of 1.0 mAh cm −2 , comparable to sulfide electrolytes but with higher oxidation stability. Additionally, Li 6 PI 3 enables stable cycling of Li//Li cells with Li 3 LuCl 6 electrolytes at 0.5 mA cm −2 for 400 cycles and maintains 86.5% capacity in Li//LiCoO 2 cells after 220 cycles at 30 °C, paving the way for high‐performance ASSLMBs.

Chemistry↗

Hydrogen bonds enhanced composite polymer electrolyte for high-voltage cathode of solid-state lithium battery

Polymer electrolyte is one of the important components for developing advanced solid-state lithium batteries (SSLBs). However, the narrow electrochemical stability window restricts the practical application with high-voltage cathodes. In this study, a series of composite solid electrolytes (CSEs), possessing both wide electrochemical stability window (up to 5.0 V vs. Li + /Li) and high ionic conductivity (over 1.35×10 -3 S/cm at 25 °C), were reported by integrating SiO 2 nanoparticles into poly(vinyl ethylene carbonate) polymer electrolyte. The enhanced anti-oxidation performances are mainly caused and confirmed by the local intermolecular interactions of hydrogen bonds in CSE. Based on this CSE, the SSLBs with LiCoO 2 cathode present good cycle stability at high voltage, and the capacity retention with 4.5 V cut-off voltage is about 94% after 200 cycles. This work not only proves the importance of intermolecular interactions in CSE, but also provides an effective method for achieving high-energy SSLBs with enhanced interface compatibility between polymer electrolyte and highvoltage cathodes

25 ENERGY STORAGE↗

Sliceable, Moldable, and Highly Conductive Electrolytes for All-Solid-State Batteries

All-solid-state batteries (ASSBs) require solid electrolytes with high ionic conductivity, stability, and deformability for optimal energy and power density. Here, we developed lithium-deficient lithium yttrium bromide (LYB) solid electrolytes, Li 3–x YBr 6–x (0 ≤ x ≤ 0.50), using a comelting method with controlled lithium deficiency. These electrolytes exhibit favorable mechanical properties such as high moldability and sliceability. The Li 2.65 YBr 5.65 composition has an ionic conductivity of 4.49 mS cm –1 at 25 °C and an activation energy of 0.28 eV. Compared to Li 3 YBr 6 , Li 2.65 YBr 5.65 demonstrates improved rate performance and cycling stability in ASSBs. High-resolution X-ray diffraction confirms the formation of the LYB phase with a C2/m space group. Structural analysis reveals increased cation disorder and larger polyhedral volumes for x > 0 in Li 3–x YBr 6–x , contributing to reduced Li + migration energy barriers. Bond valence site energy calculations and molecular dynamics simulations reveal enhanced 3D lithium-ion transport. NMR spectroscopy further highlights increased Li + dynamics and impurity elimination.

Poudel, Tej P. [Florida State Univ., Tallahassee, ↗