Ionic Conductivity of Block Copolymer Electrolytes in the Vicinity of Order−Disorder and Order−Order Transitions

Journal Article · Tue Sep 15 04:00:00 EDT 2009 · Macromolecules

DOI:https://doi.org/10.1021/ma900401a· OSTI ID:1005838

Wanakule, Nisita S; Panday, Ashoutosh; Mullin, Scott A; Gann, Eliot; Hexemer, Alex; Balsara, Nitash P

Order-order and order-disorder phase transitions in mixtures of poly(styrene-block-ethylene oxide) (SEO) copolymers and lithium bis(trifluoromethylsulfonimide) (LiTFSI), a common lithium salt used in polymer electrolytes, were studied using a combination of small-angle X-ray scattering (SAXS), birefringence, and ac impedance spectroscopy. The SEO/LiTFSI mixtures exhibit lamellar, hexagonally packed cylinders, and gyroid microphases. The molecular weight of the blocks and the salt concentration was adjusted to obtain order-order and order-disorder transition temperatures within the available experimental window. The ionic conductivities of the mixtures, normalized by the ionic conductivity of a 20 kg/mol homopolymer PEO sample at the salt concentration and temperature of interest, were independent of temperature, in spite of the presence of the above-mentioned phase transitions.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE
• OSTI ID: 1005838
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: (15) ; 08, 2009 Vol. 42
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
COPOLYMERS
ELECTROLYTES
IONIC CONDUCTIVITY
LITHIUM COMPOUNDS
MICROSTRUCTURE
MOLECULAR WEIGHT
PHASE TRANSFORMATIONS