skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Intrinsic Ion Transport Properties of Block Copolymer Electrolytes

Journal Article · · ACS Nano

Knowledge of intrinsic properties is of central importance for materials design and assessing suitability for specific applications. Self-assembling block copolymer electrolytes (BCEs) are of great interest for applications in solid-state energy storage devices. A fundamental understanding of ion transport properties, however, is hindered by the difficulty in deconvoluting extrinsic factors, such as defects, from intrinsic factors, such as the presence of interfaces between the domains. Here, we quantify the intrinsic ion transport properties of a model BCE system consisting of poly(styrene-block-ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt using a generalizable strategy of depositing thin films on interdigitated electrodes and self-assembling fully connected parallel lamellar structures throughout the films. Comparison between conductivity in homopolymer poly(ethylene oxide) (PEO)-LiTFSI electrolytes and the analogous conducting material in SEO over a range of salt concentrations (r, molar ratio of lithium ion to ethylene oxide repeat units) and temperatures reveals that between 20% and 50% of the PEO in SEO is inactive. Using mean-field theory calculations of the domain structure and monomer concentration profiles at domain interfaces-both of which vary substantially with salt concentration-the fraction of inactive PEO in the SEO, as derived from conductivity measurements, can be quantitatively reconciled with the fraction of PEO that is mixed with greater than a few volume percent of polystyrene. Despite the detrimental interfacial effects for ion transport in BCEs, the intrinsic conductivity of the SEO studied here (ca. 10-3 S/cm at 90 degrees C, r = 0.085) is an order of magnitude higher than reported values from bulk samples of similar molecular weight SEO (ca. 10-4 S/cm at 90 degrees C, r = 0.085). Finally, this work provides motivation and methods for pursuing improved BCE chemical design, interfacial engineering, and processing.

Research Organization:
Ames Lab., Ames, IA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Science Foundation (NSF)
Grant/Contract Number:
AC02-06CH11357; ECCS-1542205; DMR-1420709
OSTI ID:
1774336
Journal Information:
ACS Nano, Vol. 14, Issue 7; ISSN 1936-0851
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (61)

Effect of Molecular Weight on the Mechanical and Electrical Properties of Block Copolymer Electrolytes journal June 2007
The morphology of symmetric diblock copolymers as revealed by neutron reflectivity journal May 1990
Salt Doping in PEO-Containing Block Copolymers: Counterion and Concentration Effects journal April 2009
Ion Transport Properties of Self-Assembled Polymer Electrolytes: The Role of Confinement and Interface journal June 2013
Enhanced Conductivity via Homopolymer-Rich Pathways in Block Polymer-Blended Electrolytes journal December 2019
Determination of Lithium-Ion Distributions in Nanostructured Block Polymer Electrolyte Thin Films by X-ray Photoelectron Spectroscopy Depth Profiling journal December 2014
Domain Spacing and Composition Profile Behavior in Salt-Doped Cyclic vs Linear Block Polymer Thin Films: A Joint Experimental and Simulation Study journal September 2017
Phase Behavior of Lithium Perchlorate-Doped Poly(styrene- b -isoprene- b -ethylene oxide) Triblock Copolymers journal April 2002
Effect of Interfaces on the Melting of PEO Confined in Triblock PS- b -PEO- b -PS Copolymers journal August 2013
On the Interfacial Width in Triblock versus Diblock Copolymers:  A Neutron Reflectivity Investigation journal September 1998
Modeling of transport of small molecules in polymer blends: Application of effective medium theory journal February 1983
Effect of Grain Size on the Ionic Conductivity of a Block Copolymer Electrolyte journal July 2014
On the Composition of the Top Layer of Microphase Separated Thin PS-PEO Films journal July 2009
Charge Transport in Nanostructured PS–PEO–PS Triblock Copolymer Electrolytes journal April 2014
Rubbery Block Copolymer Electrolytes for Solid-State Rechargeable Lithium Batteries journal January 1999
Self-assembly of block copolymer thin films journal June 2010
Effect of Tapering on Morphology and Interfacial Behavior of Diblock Copolymers from Molecular Dynamics Simulations journal July 2015
Salt-doped block copolymers: ion distribution, domain spacing and effective χ parameter journal January 2012
Mechanism of Ion Transport in Amorphous Poly(ethylene oxide)/LiTFSI from Molecular Dynamics Simulations journal February 2006
Block copolymer electrolytes for rechargeable lithium batteries journal November 2013
Ionic Conductivity of Low Molecular Weight Block Copolymer Electrolytes journal January 2013
Theory of block copolymer interfaces in the strong segregation limit journal November 1993
Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes journal July 2015
Interrogation of Electrochemical Properties of Polymer Electrolyte Thin Films with Interdigitated Electrodes journal January 2018
Hyperbolic tangent variational approximation for interfacial profiles of binary polymer blends journal September 1995
An Ambient Temperature Electrolyte with Superior Lithium Ion Conductivity based on a Self-Assembled Block Copolymer journal April 2018
Isolating the Effect of Molecular Weight on Ion Transport of Non-Ionic Diblock Copolymer/Ionic Liquid Mixtures journal March 2016
Effect of Molecular Weight and Salt Concentration on Conductivity of Block Copolymer Electrolytes journal July 2009
Surface Reconstruction Limited Conductivity in Block‐Copolymer Li Battery Electrolytes journal September 2019
Unifying Weak- and Strong-Segregation Block Copolymer Theories journal January 1996
Effect of Nanoscale Morphology on the Conductivity of Polymerized Ionic Liquid Block Copolymers journal July 2011
Monte Carlo Simulations of Asymmetric Diblock Copolymer Thin Films Confined between Two Homogeneous Surfaces journal May 2001
Quantifying Lithium Salt and Polymer Density Distributions in Nanostructured Ion-Conducting Block Polymers journal February 2018
Anisotropic Ionic Conductivity in Block Copolymer Membranes by Magnetic Field Alignment journal December 2010
Anisotropic Proton Conduction in Aligned Block Copolymer Electrolyte Membranes at Equilibrium with Humid Air journal January 2010
Theoretical and experimental determination of cell constants of planar-interdigitated electrolyte conductivity sensors journal March 1995
Ion Correlation Effects in Salt-Doped Block Copolymers journal March 2018
Universal Relationship between Conductivity and Solvation-Site Connectivity in Ether-Based Polymer Electrolytes journal July 2016
Ionic Liquids as Additives to Polystyrene- Block -Poly(Methyl Methacrylate) Enabling Directed Self-Assembly of Patterns with Sub-10 nm Features journal April 2018
Probing-models for interdigitated electrode systems with ferroelectric thin films journal April 2018
Effect of Molecular Weight and Salt Concentration on Ion Transport and the Transference Number in Polymer Electrolytes journal October 2015
Organizing thermodynamic data obtained from multicomponent polymer electrolytes: Salt‐containing polymer blends and block copolymers journal February 2019
Impedance study of (PEO)10LiClO4–Al2O3 composite polymer electrolyte with blocking electrodes journal March 2001
Ionic Conductivities of Block Copolymer Electrolytes with Various Conducting Pathways: Sample Preparation and Processing Considerations journal May 2012
Characterizing the Interface Scaling of High χ Block Copolymers near the Order–Disorder Transition journal December 2017
Arrhenius-type temperature dependence of the segmental relaxation below Tg journal June 1999
Phase Diagrams and Conductivity Behavior of Poly(ethylene oxide)-Molten Salt Rubbery Electrolytes journal December 1994
Designing Polymer Electrolytes for Safe and High Capacity Rechargeable Lithium Batteries journal March 2017
Effect of monomer structure on ionic conductivity in a systematic set of polyester electrolytes journal June 2016
Leveraging Molecular Architecture To Design New, All-Polymer Solid Electrolytes with Simultaneous Enhancement in Modulus and Ionic Conductivity journal March 2018
Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains journal February 2017
Structure–Conductivity Relationships in Ordered and Disordered Salt-Doped Diblock Copolymer/Homopolymer Blends journal September 2016
Broadly Accessible Self-Consistent Field Theory for Block Polymer Materials Discovery journal June 2016
Measurement of Three Transport Coefficients and the Thermodynamic Factor in Block Copolymer Electrolytes with Different Morphologies journal January 2020
Interfacial Interaction Dependence of Microdomain Orientation in Diblock Copolymer Thin Films journal April 2005
Anisotropic Ion Diffusion and Electrochemically Driven Transport in Nanostructured Block Copolymer Electrolytes journal January 2018
Structure and Ionic Conductivity of Polystyrene- block -poly(ethylene oxide) Electrolytes in the High Salt Concentration Limit journal February 2016
Influence of molecular weight and degree of segregation on local segmental dynamics of ordered block copolymers journal January 2016
Gyroid and Other Ordered Morphologies in Single-Ion Conducting Polymers and Their Impact on Ion Conductivity journal December 2019
Thermodynamics of Block Copolymers with and without Salt journal December 2013
Role of Defects in Ion Transport in Block Copolymer Electrolytes journal June 2019