All-solid-state Li-metal batteries: role of blending PTFE with PEO and LiTFSI salt as a composite electrolyte with enhanced thermal stability

Jokhakar, Deep; Puthusseri, Dhanya; Manikandan, P.; Li, Zheng; Moon, Jooho; Weng, Hsin-Jan; Pol, Vilas G.

doi:10.1039/d0se00013b

Cited by 27 publications

(18 citation statements)

References 32 publications

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“…The curves presented in Figure d display different behaviors in the regions from 25 to 45 °C and from 45 to 65 °C. The inflection point near 45 °C is presumably due to the transformation of the PVDF/PEC blended polymer from crystalline properties to a more amorphous structure. , The amorphous phase of the polymer would promote the diffusion of Li + ions across the interchain and intrachain segments, providing many new diffusion pathways and more mobile charge carriers (because of the increased free volume) . Furthermore, it is reasonable that more Li + ion hopping sites were formed, thereby increasing the Li + ionic conductivity upon increasing the temperature.…”

Section: Results and Discussionmentioning

confidence: 99%

Freestanding Trilayer Hybrid Solid Electrolyte with Electrospun Interconnected Al-LLZO Nanofibers for Solid-State Lithium-Metal Batteries

Mengesha

Beshahwured

et al. 2021

ACS Appl. Energy Mater.

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Energy storage devices that are safe to use and thermally stable and have a wide working electrochemical window and high specific capacity would be a boon to modern society. All-solid-state lithium-metal batteries (ASSLMBs) are promising devices for energy storage because they fulfill these requirements. In this study, we used a solution-casting method to synthesize a freestanding trilayer hybrid solid-state electrolyte (Tri-HSE) membrane from a suspension of interconnected Li6.28La3Zr2Al0.24O12 (Al-LLZO, as the filler), poly(vinylidene fluoride)/poly(ethylene carbonate) (PVDF/PEC, as the blended polymer), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, as the salt), and succinonitrile (SN, as the plasticizer). The as-prepared Tri-HSE membrane exhibited a high ionic conductivity (ca. 3.91 × 10–4 S cm–1 at 25 °C), a high Li transference number (ca. 0.78), and a high tensile strength (ca. 11.36 MPa). The symmetric cell (Li/Tri-HSE/Li) was stable during Li plating/stripping cycles for 470 h without any short-circuiting. The assembled NCM811/Tri-HSE/Li full cell operated between 2.6 and 4.2 V cut-off voltages, displaying a high initial discharge capacity (162.59 mAh g–1) and a high capacity retention (92.41%) after 100 cycles at a rate of 0.1C. Also, at a rate of 0.2C, it displayed admirable capacity retentions and average Coulombic efficiencies of 87.52, 83.40 and 99.21, 99.47%, after 450 and 250 cycles, at 4.2 and 4.3 V cut-off voltages, respectively. Moreover, the 5 × 3 cm2 dimensional pouch cell assembled using the same membrane reveals an average Coulombic efficiency and capacity retention of 99.53 and 95.58% after 30 cycles, respectively. Therefore, this as-synthesized Tri-HSE membranecharacterized by high flexibility, ionic conductivity, mechanical strength, wide electrochemical window, and low in situ heat generationappears to be a promising solid-state electrolyte for upcoming generations of lithium-metal batteries operated at room temperature.

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Section: Results and Discussionmentioning

confidence: 99%

Freestanding Trilayer Hybrid Solid Electrolyte with Electrospun Interconnected Al-LLZO Nanofibers for Solid-State Lithium-Metal Batteries

Mengesha

Beshahwured

et al. 2021

ACS Appl. Energy Mater.

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“…The morphology of the polymer film after combustion demonstrated thermal stability against the extreme case. Jokhakar et al 56 conducted a polymer flammability test on PEO‐PTEE systems (Figure 4(A)). After burning, PEO completely melted, which may lead to a short circuit in practical ASSLIBs, but the CPE mixed with PTEE reflects dramatically less flammability.…”

Section: Material‐level Thermal Stability Of Sesmentioning

confidence: 99%

“…The battery with polymer electrolyte showed better thermal stability with smaller heat generation. Jokhakar et al 56 choose the same anode to compare liquid electrolyte with polymer ASSLIB, and found that SEs produced less heat than the liquid electrolyte. The total heat productions of batteries with liquid, PEO, and PTFE‐modified electrolytes were 5473, 3554, and 1970 kJ g −1 , respectively (Figure 12(B)).…”

Section: Battery‐level Thermal Stabilitymentioning

confidence: 99%

Progress in thermal stability of all‐solid‐state‐Li‐ion‐batteries

Wang

et al. 2021

InfoMat

178

108

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Thermal safety is one of the major issues for lithium‐ion batteries (LIBs) used in electric vehicles. The thermal runaway mechanism and process of LIBs have been extensively studied, but the thermal problems of LIBs remain intractable due to the flammability, volatility and corrosiveness of organic liquid electrolytes. To ultimately solve the thermal problem, all‐solid‐state LIBs (ASSLIBs) are considered to be the most promising technology. However, research on the thermal stability of solid‐state electrolytes (SEs) is still in its initial stage, and the thermal safety of ASSLIBs still needs further validation. Moreover, the specified reviews summarizing the thermal stability of ASSLIBs and all types of SEs are still missing. To fill this gap, this review systematically discussed recent progress in the field of thermal properties investigation for ASSLIBs, form levels of materials and interface to the whole battery. The thermal properties of three major types of SEs, including polymer, oxide, and sulfide SEs are systematically reviewed here. This review aims to provide a comprehensive understanding of the thermal stability of SEs for the benign development of ASSLIBs and their promising application under practical operating conditions.

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“…Linear poly(ethylene oxide) (PEO) has gained significant attention as an SPE ,− due to its excellent characteristics including fast segmental dynamics as well as the ability to form complexes with a wide range of different lithium salts. It is generally believed that ion conduction occurs in the amorphous phase where ion transport is coupled with segmental dynamics. ,,,− At room temperature, however, PEO is a semicrystalline polymer with ionic conductivity ranging between 10 –6 and 10 –8 S/cm, in which crystalline regions impede ion transport (see Figure a for scheme). The ionic conductivity increases up to 10 –3 S/cm above its melting temperature ( T m = 60 °C), yet with severe reduction in mechanical strength, which limits its application in a solid-state battery.…”

Section: Introductionmentioning

confidence: 99%

“…The ionic conductivity increases up to 10 –3 S/cm above its melting temperature ( T m = 60 °C), yet with severe reduction in mechanical strength, which limits its application in a solid-state battery. To overcome these drawbacks in relation to crystallization and mechanical stability, one method is to blend PEO with another polymer that can provide mechanical rigidity and eliminate crystallinity. ,− In this sense, a high glass transition temperature ( T g ) polymer poly(methyl methacrylate) (PMMA) is commonly used (Figure b). Incorporation of PMMA into PEO significantly increased the mechanical properties, such as storage modulus, of PEO/PMMA blends, making the liquid-like behavior of PEO to a more solid-like behavior. , …”

Section: Introductionmentioning

confidence: 99%

Effect of Polymer Topology on Microstructure, Segmental Dynamics, and Ionic Conductivity in PEO/PMMA-Based Solid Polymer Electrolytes

Bakar

Darvishi

et al. 2021

ACS Appl. Polym. Mater.

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Poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) have attracted much interest due to their high ionic conductivity resulting from inherently fast segmental dynamics and high salt solubility, yet they lack mechanical stability in their neat form. Blending PEO with another rigid, or high glass transition temperature, polymer is a versatile way to improve the mechanical stability; however, the ionic conductivity is strongly reduced due to slower segmental dynamics of highly interpenetrating linear polymer chains. In this work, we used model PEO/PMMA blend systems prepared with various well-defined PEO architectures (linear, stars, hyperbranched, and bottlebrushes) doped with lithium bis(trifluoromethane-sulfonyl)-imide (LiTFSI) and investigated, for the first time, the role of macromolecular architecture of PEO on crystallization, segmental dynamics, and ionic conductivity in the blends and electrolytes. The results suggest that room-temperature miscibility of these polymers can be dramatically extended by using nonlinear PEO in the blends instead of linear chains, which crystallize above 35 wt %. The broadband dielectric spectroscopy results revealed enhanced decoupling of PMMA and PEO segmental dynamics in compact branched architectures, which helps to achieve faster segmental motion of star PEO in glassy PMMA. This manifests as nearly three-fold higher ionic conductivity in these nonlinear blends compared to the conventional linear PEO/PMMA system. Regardless of the PEO architectures, the temperature dependence of ionic conductivity blends with PMMA and LiTFSI is well defined using the Vogel–Fulcher–Tammann mechanism, suggesting that ion transport is mainly affected by the segmental motion. The activation energy values decrease with the increasing ionic conductivity. Overall, our results show that macromolecular architecture can be a tool to decouple segmental dynamics and ion mobility to rationally design SPEs with improved performance.

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All-solid-state Li-metal batteries: role of blending PTFE with PEO and LiTFSI salt as a composite electrolyte with enhanced thermal stability

Abstract: Enhancing the ionic conductivity and thermal stability of solid electrolytes is crucial for the development of all-solid-state batteries.

Cited by 27 publications

References 32 publications

Freestanding Trilayer Hybrid Solid Electrolyte with Electrospun Interconnected Al-LLZO Nanofibers for Solid-State Lithium-Metal Batteries

Freestanding Trilayer Hybrid Solid Electrolyte with Electrospun Interconnected Al-LLZO Nanofibers for Solid-State Lithium-Metal Batteries

Progress in thermal stability of all‐solid‐state‐Li‐ion‐batteries

Effect of Polymer Topology on Microstructure, Segmental Dynamics, and Ionic Conductivity in PEO/PMMA-Based Solid Polymer Electrolytes

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