Effect of Lithium-Ion Concentration on Morphology and Ion Transport in Single-Ion-Conducting Block Copolymer Electrolytes

Rojas, Adriana A.; İnceoğlu, Şebnem; Mackay, Nikolaus G.; Thelen, Jacob L.; Devaux, Didier; Stone, G. M.; Balsara, Nitash P.

doi:10.1021/acs.macromol.5b01193

Cited by 126 publications

(140 citation statements)

References 39 publications

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“…42,43 ) The absence of crystallinity is due to the migration of the Li + ions from the PSTFSI block to the PEO block. 16,17 Similarly, the magnesiated copolymers, PEO− P[(STFSI) 2 Mg](9.5−3.6), -(9.5−5.0), and -(9.5−7.7), exhibited melting behavior (Figure 9b) while PEO−P-[(STFSI) 2 Mg](9.5−8.5) did not. As argued above, the absence of crystallinity in this case is due to the migration of Mg 2+ ions from the PSTFSI block to the PEO block.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Dependence of Morphology, Shear Modulus, and Conductivity on the Composition of Lithiated and Magnesiated Single-Ion-Conducting Block Copolymer Electrolytes

et al. 2017

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Single-ion-conducting block copolymers are of considerable interest as electrolytes for battery systems, as they eliminate overpotentials due to concentration gradients. In this study, we characterize a library of poly(ethylene oxide) (PEO)-based diblock copolymers where the second block is poly(styrene-4-sulfonyltrifluoromethylsulfonyl)imide with either cation: univalent lithium or divalent magnesium counterions (PEO−PSLiTFSI or PEO−P[(STFSI) 2 Mg]). The PEO chain length is held fixed in this study. Polymers were synthesized in matched pairs that were identical in all aspects except for the identity of the counterion. Using rheology, SAXS, DSC, and AC impedance spectroscopy, we show that the dependence of morphology, modulus, and conductivity on composition in these charged copolymer systems is fundamentally different from uncharged block copolymers. At a given frequency and temperature, the shear moduli of the magnesiated copolymer systems were approximately 3−4 orders of magnitude higher than those of the matched lithiated pair. The shear moduli of all of the lithiated copolymers showed liquid-like rheological features while the magnesiated copolymers did not. All of the lithiated copolymers were completely disordered (homogeneous), consistent with the observed rheological properties. As expected, the moduli of the lithiated copolymers increased with increasing volume fraction of the ion-containing block (ϕ PSTFSI ), and the conductivity decreased with ϕ PSTFSI . However, the magnesiated copolymers followed a distinct trend. We show that this was due to the presence of microphase separation in the regime 0.21 ≤ ϕ PSTFSI ≤ 0.36, and the tendency for microphase separation became weaker with increasing ϕ PSTFSI . The magnesiated copolymer with ϕ PSTFSI = 0.38 was homogeneous. The morphological, rheological, and conductivity properties of these systems are governed by the affinity of the cations for PEO chains; homogeneous systems are obtained when the cations migrate from the ion-containing block to PEO.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Dependence of Morphology, Shear Modulus, and Conductivity on the Composition of Lithiated and Magnesiated Single-Ion-Conducting Block Copolymer Electrolytes

et al. 2017

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“…The common way to increase the ionic conductivity is to blend them with a polymer matrix containing soft segments like PEO, in which the polymer matrix functionalizes as a transporter of Li + ions. [64][65][66] Plasticized single lithium-ion GPEs are typically prepared by swelling the resulting electrolyte membranes in PC or the mixed solvents of EC/DMC. [67] The developments of single lithium-ion conducting GPEs have demonstrated several advantages over the dual-ion GPEs with large LTNs close to unity, the absence of the detrimental effect of anion polarization, and the low rate of lithium dendrite growth.…”

Section: Single Lithium-ion Conducting Gpesmentioning

confidence: 99%

Gel Polymer Electrolytes for Electrochemical Energy Storage

Cheng

Pan

Zhao

et al. 2017

Advanced Energy Materials

780

562

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storage devices with adjustable shapes and high flexibility, which is promising for the burgeoning portable and wearable electronics. [7][8][9] Furthermore, the flexibility and elasticity of GPEs are also prone to tolerate the volume change of electrode materials and the dendrites of lithium metal during charge and discharge processes. [10][11][12][13] As a consequence, GPEs have become one of the most desirable alternatives among various electrolytes for the electrochemical energy storage devices, and significant progress has been made in lithium-ion batteries (LIBs), supercapacitors (SCs), lithium-oxygen (Li-O 2 ) batteries as well as the other kinds of electrochemical energy storage devices, such as sodium-ion batteries, lithium-sulfur batteries, fuel cells, and zinc-air batteries. [14][15][16] In order to meet the requirements of wearable devices for flexibility and deformability, more special GPEs with tough, [17] stretchable, [18] and compressible [19] functionalities have been also developed.Typically, a polymeric framework is adopted in GPEs as host material, providing high mechanical integrity. Several criteria for a good polymer host lie in: [20][21][22] (i) fast segmental motion of polymer chain; (ii) special groups promoting the dissolution of salts; (iii) low glass transition temperature (T g ); (iv) high molecular weight; (v) wide electrochemical window; (vi) high degradation temperature. Within the framework, the salts in the GPEs serve as the sources of the charge carriers, which are generally required to have large anions and low dissociation energy for easier dissociating-induced free/mobile ions. According to the types of electrolytes, there are four categories of GPEs based on proton, [23] alkaline, [24] conducting salts, and ionic liquids (ILs). [25] The criteria for an appropriate electrolyte include: [26][27][28] (i) good dissociation without forming ion pairs or ion aggregation; (ii) high thermal, chemical, and electrochemical stability; (iii) high ionic conductivity. In order to dissolve both the polymer hosts and electrolytic salts, the organic/ aqueous solvents are introduced to provide the medium for ionic conduction. A good solvent should simultaneously have high dielectric constant (ɛ > 15), donor number for more dissociation of ion and chemical and electrochemical stability. Organic solvents normally include ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dimethyl formamide (DMF), dimethyl sulphoxide, ethyl methyl carbonate, and tetrahydrofuran.To prepare a high-performance GPE, it is essential to select the species of host polymer, solvent, and electrolytic salt, and then blend them by solution or melt processes, such as casting With the booming development of flexible and wearable electronics, their safety issues and operation stabilities have attracted worldwide attentions. Compared with traditional liquid electrolytes, gel polymer electrolytes (GPEs) are preferred due to their higher safety and adaptability to the design of ...

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“…(e)), PEO‐ b ‐P(LiSTFSI) (Fig. (f)), P(LiMTFSI)‐ b ‐PEO‐ b ‐P(LiMTFSI) (LiMTFSI: lithium 1‐[3‐(methacryloyloxy)‐propylsulfonyl]‐1‐(trifluoromethanesulfonyl)imide) (Figs (g) and (h)) and POEM‐ b ‐P(LiMTFSI) (Fig. (i)) .…”

Section: Single‐ion Conducting Bcesmentioning

confidence: 99%

Poly(ethylene oxide)‐based block copolymer electrolytes for lithium metal batteries

Phan

Issa

Gigmès

2018

Polymer International

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Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid‐state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self‐assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO‐based BCEs are commonly known. There are the traditional ones, also called dual‐ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single‐lithium‐ion conducting BCEs (SIC‐BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC‐BCEs have marked advantages over dual‐ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. © 2018 Society of Chemical Industry

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Effect of Lithium-Ion Concentration on Morphology and Ion Transport in Single-Ion-Conducting Block Copolymer Electrolytes

Cited by 126 publications

References 39 publications

Dependence of Morphology, Shear Modulus, and Conductivity on the Composition of Lithiated and Magnesiated Single-Ion-Conducting Block Copolymer Electrolytes

Dependence of Morphology, Shear Modulus, and Conductivity on the Composition of Lithiated and Magnesiated Single-Ion-Conducting Block Copolymer Electrolytes

Gel Polymer Electrolytes for Electrochemical Energy Storage

Poly(ethylene oxide)‐based block copolymer electrolytes for lithium metal batteries

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