Characteristics of new-type solid polymer electrolyte controlling nano-structure

Niitani, Takeshi; Shimada, Mikiya; Kawamura, Kiyoshi; Kanamura, Kiyoshi

doi:10.1016/j.jpowsour.2005.03.102

Cited by 113 publications

(76 citation statements)

References 7 publications

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“…[23][24][25] In studies utilizing block copolymers as solid polymer electrolytes, the mechanical phase is usually made of a high glass transition temperature polymer such as polystyrene. [26][27][28][29] Extensive work on the thermodynamics of polystyrene-b-poly(ethylene oxide) (SEO) diblock copolymers [30][31][32][33] indicate that the tendency for microphase separation is enhanced by the presence of ions. 34,35 For symmetric SEO electrolytes, i.e.…”

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confidence: 99%

“…11,12 One approach for resolving this problem is the use of a block copolymer electrolyte. [13][14][15][16][17][18][19][20][21][22] Immiscibility between the blocks induces microphase separation, producing hard insulating phases interspersed with soft, ionically conductive phases. [23][24][25] In studies utilizing block copolymers as solid polymer electrolytes, the mechanical phase is usually made of a high glass transition temperature polymer such as polystyrene.…”

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confidence: 99%

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Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Devaux

Harry

Parkinson

et al. 2015

J. Electrochem. Soc.

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Solid block polymer electrolytes are promising candidates for the development of high energy density rechargeable lithium metal based batteries. All solid-state batteries comprising lithium metal negative electrode and lithium iron phosphate (LiFePO 4 ) composite positive electrode were assembled. A polystyrene-b-poly(ethylene oxide) (SEO) copolymer doped with a lithium salt was used as the electrolyte. After cycling the batteries, the reason for capacity fade and failure was determined by imaging the batteries using synchrotron hard X-ray microtomography. These experiments revealed partial delamination of the lithium foil and the block copolymer electrolyte layer. The void volume between the foil and electrolyte layer obtained after 40 to 90 cycles is comparable to volume change in the battery during one cycle. A simple model to account for the effect of delamination on current density in the battery is presented. Capacity fade and battery failures observed in our experiments are consistent with this model. No evidence of lithium dendrite formation was found. In contrast, cycled lithium-lithium symmetric cells with the same polymer electrolyte at the same current density failed due to dendrite formation. No evidence of delamination was found in these cells. Solid polymer electrolytes are promising candidates for the development of high performance rechargeable batteries comprising a lithium (Li) metal electrode due to their chemical stability toward lithium and their mechanical resistance to dendrite growth.1-3 After the pioneering work by Fenton et al., 4 where poly(ethylene oxide) (PEO) laden with alkali metal salts was shown to possess good ionic conductivity, its application as a polymer electrolyte in a full cell was demonstrated by Armand et al. [5][6][7] PEO is a semi-crystalline polymer at room temperature. Ionic transport in PEO electrolytes is linked to segmental motion of the polymer chains, 8,9 and occurs predominantly in the amorphous phase.10 Thus solid polymer electrolyte based batteries must be operated at temperatures (T) above the PEO melting temperature. However, amorphous PEO is too soft to avoid short circuit due to lithium dendrite growth. 11,12 One approach for resolving this problem is the use of a block copolymer electrolyte. [13][14][15][16][17][18][19][20][21][22] Immiscibility between the blocks induces microphase separation, producing hard insulating phases interspersed with soft, ionically conductive phases. [23][24][25] In studies utilizing block copolymers as solid polymer electrolytes, the mechanical phase is usually made of a high glass transition temperature polymer such as polystyrene. [26][27][28][29] Extensive work on the thermodynamics of polystyrene-b-poly(ethylene oxide) (SEO) diblock copolymers [30][31][32][33] indicate that the tendency for microphase separation is enhanced by the presence of ions. 34,35 For symmetric SEO electrolytes, i.e. copolymers wherein the volume fraction of the conducting phase is above 50%, the ionic conductivity has been shown to increase wit...

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confidence: 99%

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Devaux

Harry

Parkinson

et al. 2015

J. Electrochem. Soc.

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“…Molecular architectures such as comb-like copolymers [15,16], cross-linked polymer networks [17,18], graft copolymers [19][20][21][22], and block copolymers [19,23] have been investigated for use as electrolytes in an attempt to independently tune the structural and transport properties. In many cases immiscibility between the blocks induces microphase separation [24][25][26], producing ordered morphologies on the nanometer length scale [27].…”

Section: Introductionmentioning

confidence: 99%

“…In studies utilizing block copolymers as SPE, the archetypal mechanical phase is made of a polymer with a high glass transition temperature (T g ) such as polystyrene (PS) [23,[28][29][30][31][32][33]. For symmetric PS-PEO diblock copolymers [30][31][32][33] (SEO), the ionic conductivity σ has been shown to increase with PEO chain length and a plateau value is reached as the molecular weight of the PEO block exceeds 100 kg/mol.…”

Section: Introductionmentioning

confidence: 99%

Investigating polypropylene-poly(ethylene oxide)-polypropylene triblock copolymers as solid polymer electrolytes for lithium batteries

et al. 2014

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Syndiotactic polypropylene-b-poly(ethylene oxide)-b-syndiotactic polypropylene (PEOP) triblock copolymers were synthesized and solid polymer electrolytes were prepared by mixing with lithium bis(trifluoromethane) sulfonimide (LiTFSI) salt. PEOP formed strongly-segregated morphologies in the absence and presence of LiTFSI. LiTFSI inhibited poly(ethylene oxide) crystallization without affecting polypropylene crystallinity. The conductivity exhibited a non-monotonic dependence on molecular weight (M n ) with a maximum near 20 kg/mol. In contrast, polystyrene-b-poly(ethylene oxide) electrolytes exhibit conductivity increasing monotonically with M n , up to a plateau in the high-M n limit. This suggests that non-conducting semi-crystalline microphases interfere with conducting pathways, while non-conducting amorphous microphases formed well-connected conducting pathways.Published by Elsevier B.V.

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“…[35][36][37] One approach to resolve this problem is the use of a nanostructured block copolymer electrolyte with rigid non-conducting domains and rubbery-conducting domains. [37][38][39][40][41][42] This study reports on the characterization of batteries comprising a Li metal negative electrode, a nanostructured block copolymer electrolyte film made by mixing polystyrene-b-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and α-Cu 6.9 V 6 O 18.9 (α-CuVO 3 for simplicity) as positive active material. The composite positive electrode contains α-CuVO 3 mixed with SEO electrolyte and carbon black.…”

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Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

Devaux

Wang

Thelen

et al. 2016

J. Electrochem. Soc.

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Lithium (Li) batteries comprising multivalent positive active materials such as copper vanadium oxide have high theoretical capacity. These batteries with a conventional liquid electrolyte exhibit limited cycle life because of copper dissolution into the electrolyte. We report here on the characterization of solid-state Li metal batteries with a positive electrode based on α-Cu 6.9 V 6 O 18.9 (α-CuVO 3 ). We replaced the liquid electrolyte by a nanostructured solid block copolymer electrolyte comprising of a mixture of polystyreneb-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. In situ X-ray diffraction was used to follow the Li insertion/de-insertion mechanism into the α-CuVO 3 host material and its reversibility. In situ X-ray scattering revealed that the multistep electrochemical reactions involved are similar in the presence of liquid or solid electrolyte. The capacity fade of the solid-state batteries is less rapid than that of α-CuVO 3 -Li metal batteries with a conventional liquid electrolyte. Hard X-ray microtomography revealed that upon cycling, voids and Cu-rich agglomerates were formed at the interface between the Li metal and the SEO electrolyte. The void volume and the volume occupied by the Cu-rich agglomerates were independent of C-rate and cycle number. There is considerable interest in copper vanadium oxide (CuVO) positive electrodes for rechargeable lithium (Li) batteries. In principle, this material can exhibit high capacity due to multistep electrochemical reactions with Li + ions. In pioneering work, Yamaki and coworkers reported on reversible Li insertion and removal in CuVO compounds.1-3 They showed that a battery comprising a Li metal negative electrode, β-Cu 2 V 2 O 7 positive electrode, and a conventional liquid electrolyte (a mixture of LiClO 4 in propylene carbonate and dimethoxyethane) could be cycled 100 times at 0.5 mA/cm 2 , with an average delivered capacity of 260 mAh/g. The battery failed abruptly due to a short which was attributed to the deposition of Cu metal on the Li electrode. These studies spark considerable interest in CuVO electrodes. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] In a more recent study, Morcrette et al. showed reversible insertion of 6 Li into Cu 2.33 V 4 O 11 through a reversible Cu extrusion-insertion process.18 During the discharge step, the Li + ions enter the host material and the copper ions are pushed to the material edges where they are reduced, forming Cu metal dendrites. During the charge step, Cu metal is oxidized, producing copper ions that re-enter the host material. This original study opened a new class of CuVO materials. 19-21However, for practical applications, battery failure due to dissolution of Cu into the liquid electrolyte and subsequent plating on the Li electrode needs to be addressed.The potential to use poly(ethylene oxide) (PEO) as an electrolyte in Li batteries was demonstrated by Fenton et al. 22 and Armand et al. 23,24 While most of the studies on PEO-based electrolytes emplo...

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Characteristics of new-type solid polymer electrolyte controlling nano-structure

Cited by 113 publications

References 7 publications

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Investigating polypropylene-poly(ethylene oxide)-polypropylene triblock copolymers as solid polymer electrolytes for lithium batteries

Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

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