Conductivity of carbonate- and perfluoropolyether-based electrolytes in porous separators

JOURNAL OF POWER SOURCES

卷:323

Article

Devaux, Didier^1,2,3  Chang, Yu H.^1,3  Villaluenga, Irune^1,2,3  Chen, X. Chelsea⁴  Chintapalli, Mahati^4,5  DeSimone, Joseph M.^6,7  Balsara, Nitash P.^1,2,3,4 

[1] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA

[2] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, JCESR, Berkeley, CA 94720 USA

[3] Univ Calif Berkeley, Dept Chem & Biomol Engn, Berkeley, CA 94720 USA

[4] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA

[5] Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA

[6] Univ N Carolina, Dept Chem, CB 3290, Chapel Hill, NC 27599 USA

[7] N Carolina State Univ, Dept Chem & Biomol Engn, Raleigh, NC 27695 USA

关键词: Perfluoropolyether;    Conductivity;    Separators;    Battery;    Polyolefin;    Polytetrafluoroethylene;   

DOI  :  10.1016/j.jpowsour.2016.05.039

来源: Elsevier

【 摘 要 】

In lithium batteries, a porous separator filled with an electrolyte is placed in between the electrodes. Properties of the separator such as porosity and wettability strongly influence the conductivity of the electrolyte-separator composite. This study focuses on three commercial separators: a single layer polypropylene (Celgard 2500), a trilayer polypropylene-polyethylene-polypropylene (PP-PE-PP), and a porous polytetrafluoroethylene (PTFE). Electron microscopy was used to characterize the pore structure, and these experiments reveal large differences in pore morphology. The separators were soaked in both carbonate- and perfluoropolyether-based electrolytes. The conductivity of the neat electrolytes (sigma(0)) varied from 6.46 x 10(-6) to 1.76 x 10(-2) S cm(-1). The porosity and wettability of the separator affect the electrolyte uptake that in turn affect the conductivity of electrolyte-separator composites. The conductivity of the electrolyte-separator composites (sigma) was found to follow a master equation, sigma = 0.51. sigma(0).phi(3.2 +/- 0.2)(c), where phi(c) is the volume fraction of the electrolyte in each separator. (C) 2016 Elsevier B.V. All rights reserved.

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