Free-standing Li<sup>+</sup>-conductive films based on PEO–PVDF blends

Ushakova, E. E.; Sergeev, Artem V.; Morzhukhin, Artem; Napolskiy, Filipp S.; Kristavchuk, Olga; Chertovich, Alexander V.; Yashina, Lada V.; Itkis, Daniil M.

doi:10.1039/d0ra02325f

Cited by 21 publications

(14 citation statements)

References 36 publications

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“…[35,36] In addition, the COC signal of PEO at 952 cm −1 is weakened significantly upon incorporating the PVDF fiber network, implying a strong interaction between PVDF and PEO due to the HF hydrogen bonding (Figure S2, Supporting Information). [33,37] The good affinity of PVDF and PEO originating from hydrogen bonds can facilitate the infusion process of the electrolyte into the PVDF fiber network and reduce the crystallinity of the PEO polymer. [24] Moreover, the thermogravimetric analysis (TGA) shows that introducing ceramic particles and PVDF fiber network can greatly improve the thermal stability of the PEO electrolyte (Figure 3c).…”

Section: Materials Characterizationsmentioning

confidence: 99%

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

Lin

Sun

et al. 2021

Advanced Energy Materials

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flammable organic liquid electrolytes to solid-state electrolytes not only endows all-solid-state lithium batteries (ASSLBs) with considerable improvements in battery safety, but also potentially allows the use of Li metal anode, which is regarded as the ultimate anode due to its high theoretical specific capacity (3860 mAh g -1 ) and low electrochemical potential (−3.04 V versus standard hydrogen electrode). [3][4][5][6][7] Thus, ASSLBs have been widely exploited as next-generation energy storage technologies with enhanced energy density and safety. [8] However, current ASSLBs are far from competitive with commercial LIBs in terms of battery performance and ease of manufacturing. [9,10] This is because conventional ASSLB assembly requires laborious fabrication of solid electrolyte and electrodes separately, followed by stacking each component together, which inevitably results in poor interfacial contact. [11,12] Radically different from LIBs, solid electrolyte in ASSLBs cannot spontaneously wet the electrodes as liquid electrolyte does, leading to discontinuous ion transport at the cathode/solid electrolyte interfaces and inside the porous cathode, which results in a large interfacial resistance and low active material utilization. [13] As a consequence, the mass loading of most reported ASSLBs is too low (usually <4 mg cm -2 ) to meet the requirement for practical energy-dense batteries. [14] In addition, due to unfavorable mechanical properties, typical solid electrolytes need to be fabricated to be overly thick as a way of ensuring their integrity under unavoidable stress during conventional cell assembly processes. [9,15] For instance, pure ceramic solid electrolytes are generally too brittle to be produced with a thickness less than 100 µm. [16,17] Although blending the ceramics with polymers can endow the composite solid electrolyte with good flexibility, it is still challenging to reduce the thickness to be comparable with that of separators (usually <30 µm) in current LIBs, which, as a result, considerably sacrifices the battery energy density. [15,18] Even worse, the inferior mechanical strength of solid electrolytes renders a poor Li dendrite suppression capability, resulting in poor cyclability of the battery. [19] These limitations of conventional ASSLB manufacturing impose a great penalty on the attainable energy density and cyclability of the battery.To address these issues, several strategies have been developed for ASSLBs. For instance, Hu et al. reported on a dense/ porous bilayer garnet electrolyte, where the porous layer served Current all-solid-state lithium battery (ASSLB) manufacturing typically involves laborious fabrication and assembly of individual electrodes and solid electrolyte, which inevitably result in large interfacial resistances. Moreover, due to the unfavorable mechanical strength, most solid electrolytes are fabricated to be overly thick and are incapable of retarding lithium dendrite formation. These factors limit the attainable energy density and cyclability of ASSLBs. Her...

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Section: Materials Characterizationsmentioning

confidence: 99%

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

Lin

Sun

et al. 2021

Advanced Energy Materials

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“…The CF 3 bending region (1160 to 1240 cm −1 ) of the operando ATR‐IR spectra shows distinct peaks at 1199 cm −1 throughout the potential range tested (Figure 2a). We assigned the peak to the CF 3 bending of the TFSA anion, [ 28 ] supported by the observation of a similar feature at 1188 cm −1 for bulk PEO 10 LiTFSA electrolyte (Green). Note that the CF 3 bending peak of operando ATR‐IR spectra was slightly (≈11 cm −1 ) shifted to the lower wavenumber than that of bulk spectra.…”

Section: Resultsmentioning

confidence: 69%

(Electro)Chemical Processes of Poly(Ethylene Oxide)‐Based Electrolyte on Cu Surface during Lithium Secondary Battery Operation

2023

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Understanding the surface electrochemistry of polymer electrolytes under battery operating conditions is of great importance for tuning the solid electrolyte interphase (SEI) in lithium batteries with polymer electrolytes. Herein, the surface (electro)chemical process of poly(ethylene oxide) (PEO) lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) (PEO10LiTFSA) electrolyte on the Cu electrode is studied by operando attenuated total reflection infrared (ATR‐IR) and ex situ X‐ray photoelectron spectroscopy (XPS) techniques coupled with the interfacial resistance obtained from electrochemical impedance spectroscopy (EIS). Linear sweep voltammogram of the Cu electrode in PEO10LiTFSA electrolyte suggests the SEI‐like layer formation involves three reduction steps. Operando ATR‐IR, ex situ XPS, and EIS reveal the corresponding (electro)chemical processes and their effect on the interfacial resistance; LiTFSA and residual H2O and CO2 are first reduced, forming an inorganic SEI‐like layer without affecting the interfacial resistance. Subsequently, the PEO matrix reduces into several decomposed products, including CC components, responsible for the most resistive SEI‐like layer. Finally, PEO‐decomposed species with CC components further reduce into alkyl‐related species, leading significant reduction of the resistance of the SEI‐like layer. The study successfully reveals the complex surface (electro)chemical process at the PEO electrolyte–Cu electrode interface, and may serve as a model system for understanding SEI component and interfacial resistance relationship in the polymer electrolyte system.

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“…The interaction between SN and Li + facilitates the dissociation of LiDFOB and the rapid release of more Li ions, which is advantageous to the rapid transfer of Li ions at room temperature. [ 2a,17 ]…”

Section: Resultsmentioning

confidence: 99%

Li‐Ion Transfer Mechanism of Ambient‐Temperature Solid Polymer Electrolyte toward Lithium Metal Battery

Wang

Sun

Zhang

et al. 2023

Advanced Energy Materials

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to ultimately solve these issues with their intrinsically high safety owing to the nonflammability and high mechanical properties. Without the defects of inorganic solid electrolytes including high brittleness and poor interfacial contact, solid polymer electrolytes (SPEs) presenting the following merits: 1) flexibility and easy scalability for fabricating flexible solid-state Li batteries, [3] 2) high safety with the low risk of combustion and leakage, [4] 3) strong mechanical properties to resist dendrite growth, [5] 4) adaptability with high energy density cathode system, [6] and 5) thermodynamic stability in a wide temperature range. [7] However, the conventional SPE such as polyethylene oxide (PEO) has the limited chain motion and a low ionic conductivity (10 −7 -10 −8 S cm −1 ) at room temperature, which requires high working temperature of ≈60 °C and therefore the wide application is restricted. [8] Extensive strategies have been proposed to achieve high-performances, such as molecular structure construct, [9] functional group design, [10] and interfacial engineering. [6a,11] Filler addition has been advanced to improve the ionic conductivity of SPEs by interrupting the segment regularity and improving the motion of polymer chain. [12] However, the rapid Li ion transfer channels are still in insufficiency within the overall polymer matrix. Succinonitrile (SN) has been used as the additive or plasticizer in polymer electrolyte to improve the ambient performance of SPEs. [13] Some researchers report that SN is conducive to weaken the strong complexation between Li ions and SPEs and therefore the migration of Li ions is promoted. [13a,14] Nevertheless, the specific working principle is still veiled.Herein, a heterogeneous dual-layer solid polymer electrolyte (DSPE) is developed in this work to clarify the working mechanism of SPEs at room temperature and match with high working potential cathode. Given the high conductivity but the corrosion effect on aluminum collectors of Lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and the excellent cathode compatibility of lithium difluoro(oxalato) borate (LiDFOB). [15] In as-prepared DSPE, the SN-PPC (poly(propylene carbonate))-LiDFOB (hereinafter referred to as DSPE-I) contacts with cathode. In addition, the PEO-Li 7 La 3 Zr 2 O 12 -LiTFSI composite electrolyte (hereinafter referred to as DSPE-II) is near lithium anode. The The low ionic conductivity and short service life of solid polymer electrolytes (SPEs) limit the application of ambient-temperature polymer lithium metal batteries, which is perhaps a result of the inherent restricted segment movement of the polymer at room temperature. Herein, an ambient-temperature dual-layer solid polymer electrolyte is developed and the related working mechanisms are innovatively investigated. In the strategy, poly(propylene carbonate) (PPC)/succinonitrile (SN) contacts with the cathode while polyethylene oxide (PEO)/Li 7 La 3 Zr 2 O 12 is adopted near the anode. Molecular dynamics simulations demonstrate the f...

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Free-standing Li⁺-conductive films based on PEO–PVDF blends

Abstract: Addition of PVDF to LiTFSI–PEO solid electrolytes enables preparation of free-standing films with the compositions within the so called “crystallinity gap” of LiTFSI–PEO system. Such films possess ionic conductivity of about 0.3 mS cm−1 at 60 °C.

Cited by 21 publications

References 36 publications

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

(Electro)Chemical Processes of Poly(Ethylene Oxide)‐Based Electrolyte on Cu Surface during Lithium Secondary Battery Operation

Li‐Ion Transfer Mechanism of Ambient‐Temperature Solid Polymer Electrolyte toward Lithium Metal Battery

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Free-standing Li+-conductive films based on PEO–PVDF blends

Abstract: Addition of PVDF to LiTFSI–PEO solid electrolytes enables preparation of free-standing films with the compositions within the so called “crystallinity gap” of LiTFSI–PEO system. Such films possess ionic conductivity of about 0.3 mS cm−1 at 60 °C.

Cited by 21 publications

References 36 publications

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

A High‐Capacity, Long‐Cycling All‐Solid‐State Lithium Battery Enabled by Integrated Cathode/Ultrathin Solid Electrolyte

(Electro)Chemical Processes of Poly(Ethylene Oxide)‐Based Electrolyte on Cu Surface during Lithium Secondary Battery Operation

Li‐Ion Transfer Mechanism of Ambient‐Temperature Solid Polymer Electrolyte toward Lithium Metal Battery

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Free-standing Li⁺-conductive films based on PEO–PVDF blends