Morphology鈥揅onductivity Relationship of Single-Ion-Conducting Block Copolymer Electrolytes for Lithium Batteries

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• 作者：Sebnem Inceoglu ; Adriana A. Rojas ; Didier Devaux ; X. Chelsea Chen ; Greg M. Stone ; Nitash P. Balsara
• 刊名：ACS Macro Letters
• 出版年：2014
• 出版时间：June 17, 2014
• 年：2014
• 卷：3
• 期：6
• 页码：510-514
• 全文大小：384K
• 年卷期：v.3,no.6(June 17, 2014)
• ISSN：2161-1653

文摘

A significant limitation of rechargeable lithium-ion batteries arises because most of the ionic current is carried by the anion, the ion that does not participate in energy-producing reactions. Single-ion-conducting block copolymer electrolytes, wherein all of the current is carried by the lithium cations, have the potential to dramatically improve battery performance. The relationship between ionic conductivity and morphology of single-ion-conducting poly(ethylene oxide)-b-polystyrenesulfonyllithium(trifluoromethylsulfonyl)imide (PEO鈥揚SLiTFSI) diblock copolymers was studied by small-angle X-ray scattering and ac impedance spectroscopy. At low temperatures, an ordered lamellar phase is obtained, and the 鈥渕obile鈥?lithium ions are trapped in the form of ionic clusters in the glassy polystyrene-rich microphase. An increase in temperature results in a thermodynamic transition to a disordered phase. Above this transition temperature, the lithium ions are released from the clusters, and ionic conductivity increases by several orders of magnitude. This morphology鈥揷onductivity relationship is very different from all previously published data on published electrolytes. The ability to design electrolytes wherein most of the current is carried by the lithium ions, to sequester them in nonconducting domains and release them when necessary, has the potential to enable new strategies for controlling the charge鈥揹ischarge characteristics of rechargeable lithium batteries.