scholarly journals Low Frequency Dielectric Relaxation and Conductance of Solid Polymer Electrolytes with PEO and Blends of PEO and PMMA

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1009 ◽  
Author(s):  
Chin Han Chan ◽  
Hans-Werner Kammer

Solid polymer electrolytes are mixtures of polymer and inorganic salt. There are quite a number of studies dealing with the relationship between electric conductivity and structural relaxation in solid polymer electrolytes. We present a phenomenological approach based on fluctuation-dissipation processes. Phase heterogeneity appears in poly(ethylene oxide) (PEO) of high molecular mass and its blends due to crystallization and accompanying phase segregation. Addition of salt hampers crystallization, causing dynamic heterogeneity of the salt mixtures. Conductivity is bound to amorphous phase; the conductivity mechanism does not depend on content of added salt. One observes dispersion of conductivity relaxation only at low frequency. This is also true for blends with poly(methyl methacrylate) (PMMA). In blends, the dynamics of relaxation depend on glass transition of the system. Glassy PMMA hampers relaxation at room temperature. Relaxation can only be observed when salt content is sufficiently high. As long as blends are in rubbery state at room temperature, they behave PEO-like. Blends turn into glassy state when PMMA is in excess. Decoupling of long-ranging and dielectric short-ranging relaxation can be observed. Conductivity mechanism in PEO, as well as in blends with PMMA were analyzed in terms of complex impedance Z*, complex permittivity, tangent loss spectra and complex conductivity.

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Qolby Sabrina ◽  
Titik Lestariningsih ◽  
Christin Rina Ratri ◽  
Achmad Subhan

Solid polymer electrolyte (SPE) appropriate to solve packaging leakage and expansion volume in lithium-ion battery systems. Evaluation of electrochemical performance of SPE consisted of mixture lithium salt, solid plasticizer, and polymer precursor with different ratio. Impedance spectroscopy was used to investigate ionic conduction and dielectric response lithium bis(trifluoromethane)sulfony imide (LiTFSI) salt, and additive succinonitrile (SCN) plasticizer. The result showing enhanced high ionic conductivity. In half-cell configurations, wide electrochemical stability window of the SPE has been tested. Have stability window at room temperature, indicating great potential of SPE for application in lithium ion batteries. Additive SCN contribute to forming pores that make it easier for the li ion to move from the anode to the cathode and vice versa for better perform SPE. Pore of SPE has been charaterization with FE-SEM. Additive 5% w.t SCN shows the best ionic conductivity with 4.2 volt wide stability window and pretty much invisible pores.


2018 ◽  
Vol 96 (7) ◽  
pp. 786-791 ◽  
Author(s):  
Kemal Ulutaş ◽  
Ugur Yahsi ◽  
Hüseyin Deligöz ◽  
Cumali Tav ◽  
Serpil Yılmaztürk ◽  
...  

In this study, it was aimed to prepare a series of PVdF-co-HFP based electrolytes with different LiClO4 loadings and to investigate their chemical and electrical properties in detail. For this purpose, PVdF-co-HFP based electrolytes with different LiClO4 loadings (1–20 weight %) were prepared using solution casting method. X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric (TGA) –differential thermal and dielectric spectroscopy analysis of PVdF-co-HFP/LiClO4 were performed to characterize their structural, thermal, and dielectric properties, respectively. XRD results showed that the diffraction peaks of PVdF-co-HFP/LiClO4 electrolytes broadened and decreased with LiClO4. TGA patterns exhibited that PVdF-co-HFP/LiClO4 electrolytes with 20 wt % of LiClO4 had the lowest thermal stability and it degraded above 473 K, which is highly applicable for solid polymer electrolytes. Dielectric constant, dielectric loss, and conductivities were calculated by measuring capacitance and dielectric loss factor of PVdF-co-HFP/LiClO4 in the range from 10 mHz to 20 MHz frequencies at room temperature. In consequence, conductivities of PVdF-co-HFP/LiClO4 increased significantly with frequency for low loading of LiClO4 while they only slightly changed with higher LiClO4 addition. On the other hand, dielectric constant values of PVdF-co-HFP/LiClO4 films decreased with frequency whereas they rose with LiClO4 addition. The dielectric studies showed an increase in dielectric constant and dielectric loss with decreasing frequency. This result was attributed to high contribution of charge accumulation at the electrode–electrolyte interface. The electrolyte showed the maximum conductivity of 8 × 10−2 S/cm at room temperature.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1089 ◽  
Author(s):  
Jierui Liang ◽  
Ke Xu ◽  
Swati Arora ◽  
Jennifer E. Laaser ◽  
Susan K. Fullerton-Shirey

A gateless lateral p-n junction with reconfigurability is demonstrated on graphene by ion-locking using solid polymer electrolytes. Ions in the electrolytes are used to configure electric-double-layers (EDLs) that induce p- and n-type regions in graphene. These EDLs are locked in place by two different electrolytes with distinct mechanisms: (1) a polyethylene oxide (PEO)-based electrolyte, PEO:CsClO4, is locked by thermal quenching (i.e., operating temperature < Tg (glass transition temperature)), and (2) a custom-synthesized, doubly-polymerizable ionic liquid (DPIL) is locked by thermally triggered polymerization that enables room temperature operation. Both approaches are gateless because only the source/drain terminals are required to create the junction, and both show two current minima in the backgated transfer measurements, which is a signature of a graphene p-n junction. The PEO:CsClO4 gated p-n junction is reconfigured to n-p by resetting the device at room temperature, reprogramming, and cooling to T < Tg. These results show an alternate approach to locking EDLs on 2D devices and suggest a path forward to reconfigurable, gateless lateral p-n junctions with potential applications in polymorphic logic circuits.


2020 ◽  
Vol 4 (3) ◽  
pp. 44
Author(s):  
Xinyi Mei ◽  
Wendy Zhao ◽  
Qiang Ma ◽  
Zheng Yue ◽  
Hamza Dunya ◽  
...  

Three new crosslinked polystyrene nanoparticles covalently attached with low lattice energy lithium salt moieties were synthesized: poly(styrene lithium trifluoromethane sulphonyl imide) (PSTFSILi), poly(styrene lithium benzene sulphonyl imide) (PSPhSILi), and poly(styrene lithium sulfonyl-1,3-dithiane-1,1,3,3-tetraoxide) (PSDTTOLi). A series of solid polymer electrolytes (SPEs) were formulated by mixing these lithium salts with high molecular weight poly(ethylene oxide), poly(ethylene glycol dimethyl ether), and lithium bis(fluorosulfonyl)imide. The crosslinked nano-sized polymer salts improved film strength and decreased the glass transition temperature (Tg) of the polymer electrolyte membranes. An enhancement in both ionic conductivity and thermal stability was observed. For example, the SPE film containing PSTFSILi displayed ionic conductivity of 7.52 × 10−5 S cm−1 at room temperature and 3.0 × 10−3 S cm−1 at 70 °C, while the SPE film containing PSDTTOLi showed an even better performance of 1.54 × 10−4 S cm−1 at room temperature and 3.23 × 10−3 S cm−1 at 70 °C.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xi Chelsea Chen ◽  
Robert L. Sacci ◽  
Naresh C. Osti ◽  
Madhusudan Tyagi ◽  
Yangyang Wang ◽  
...  

Solid polymer electrolytes are promising in fulfilling the requirements for a stable lithium metal anode toward higher energy and power densities. In this work, we investigate the segmental dynamics, ionic conductivity, and crystallinity of a polymer electrolyte consisting of poly(ethylene oxide) (PEO) and lithium triflate salt, in the semi-crystalline state. Using quasi-elastic neutron scattering, the segmental dynamics of PEO chains confined between the crystalline lamellae is quantified, using Cole–Cole analysis. We show that the structural relaxation time, τ0, of PEO equilibrated near room temperature is six-fold longer than the same sample that had just cooled down to room temperature. This corresponds to a three-fold smaller ionic conductivity in the equilibrated condition. This work reveals that the segmental dynamics of semi-crystalline polymer electrolytes is very sensitive to thermal history. We demonstrate that quasi-elastic neutron scattering can be used to characterize the ion transport and segmental dynamics in the semi-crystalline state.


2016 ◽  
Vol 49 (6) ◽  
pp. 513-526 ◽  
Author(s):  
Asheesh Kumar ◽  
Raghunandan Sharma ◽  
M Suresh ◽  
Malay K Das ◽  
Kamal K Kar

Polymer electrolytes consisting of poly(vinylidene fluoride-co-hexafluoropropylene) in combination with lithium triflate (LiCF3SO3) salt of varying concentration have been prepared using the conventional solution casting technique in the argon atmosphere. Structural electrical characterizations of the synthesized electrolytes have been performed using various imaging and spectroscopic techniques. The DC conductivities determined by complex impedance plots reveal gradual increase with increase in salt concentration up to a particular limit and decrease subsequently. The maximum DC conductivity obtained at 300 K is 1.64 × 10−4 Scm−1 for the electrolyte with a polymer to salt weight ratio of 1:1.8. The temperature-dependent conductivity followed a mixed Arrhenius and Vogel–Tamman–Fulcher type behaviour for the polymer electrolytes. From the Summerfield master curve plot, the conductivity of the solid polymer electrolytes is found to depend not only on ion dynamics but also on the segmental mobility of the polymer chains.


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