Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

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

References (64)

Surface Reconstruction Limited Conductivity in Block‐Copolymer Li Battery Electrolytes journal September 2019
An Ambient Temperature Electrolyte with Superior Lithium Ion Conductivity based on a Self-Assembled Block Copolymer journal April 2018
Modeling of transport of small molecules in polymer blends: Application of effective medium theory journal February 1983
Block copolymer electrolytes for rechargeable lithium batteries journal November 2013
Influence of molecular weight and degree of segregation on local segmental dynamics of ordered block copolymers journal January 2016
Organizing thermodynamic data obtained from multicomponent polymer electrolytes: Salt‐containing polymer blends and block copolymers journal February 2019
Theoretical and experimental determination of cell constants of planar-interdigitated electrolyte conductivity sensors journal March 1995
Impedance study of (PEO)10LiClO4–Al2O3 composite polymer electrolyte with blocking electrodes journal March 2001
Self-assembly of block copolymer thin films journal June 2010
Effect of monomer structure on ionic conductivity in a systematic set of polyester electrolytes journal June 2016
Designing Polymer Electrolytes for Safe and High Capacity Rechargeable Lithium Batteries journal March 2017
Anisotropic Ion Diffusion and Electrochemically Driven Transport in Nanostructured Block Copolymer Electrolytes journal January 2018
Measurement of Three Transport Coefficients and the Thermodynamic Factor in Block Copolymer Electrolytes with Different Morphologies journal January 2020
Effect of Molecular Weight and Salt Concentration on Ion Transport and the Transference Number in Polymer Electrolytes journal October 2015
Isolating the Effect of Molecular Weight on Ion Transport of Non-Ionic Diblock Copolymer/Ionic Liquid Mixtures journal March 2016
Structure and Ionic Conductivity of Polystyrene- block -poly(ethylene oxide) Electrolytes in the High Salt Concentration Limit journal February 2016
Broadly Accessible Self-Consistent Field Theory for Block Polymer Materials Discovery journal June 2016
Universal Relationship between Conductivity and Solvation-Site Connectivity in Ether-Based Polymer Electrolytes journal July 2016
Structure–Conductivity Relationships in Ordered and Disordered Salt-Doped Diblock Copolymer/Homopolymer Blends journal September 2016
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
Characterizing the Interface Scaling of High χ Block Copolymers near the Order–Disorder Transition journal December 2017
Leveraging Molecular Architecture To Design New, All-Polymer Solid Electrolytes with Simultaneous Enhancement in Modulus and Ionic Conductivity journal March 2018
Quantifying Lithium Salt and Polymer Density Distributions in Nanostructured Ion-Conducting Block Polymers journal February 2018
Enhanced Conductivity via Homopolymer-Rich Pathways in Block Polymer-Blended Electrolytes journal December 2019
Role of Defects in Ion Transport in Block Copolymer Electrolytes journal June 2019
Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains journal February 2017
Ionic Liquids as Additives to Polystyrene- Block -Poly(Methyl Methacrylate) Enabling Directed Self-Assembly of Patterns with Sub-10 nm Features journal April 2018
Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes journal July 2015
Phase Behavior of Lithium Perchlorate-Doped Poly(styrene- b -isoprene- b -ethylene oxide) Triblock Copolymers journal April 2002
Anisotropic Ionic Conductivity in Block Copolymer Membranes by Magnetic Field Alignment journal December 2010
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
Ion Transport Properties of Self-Assembled Polymer Electrolytes: The Role of Confinement and Interface journal June 2013
Effect of Interfaces on the Melting of PEO Confined in Triblock PS- b -PEO- b -PS Copolymers journal August 2013
Theory of block copolymer interfaces in the strong segregation limit journal November 1993
Phase Diagrams and Conductivity Behavior of Poly(ethylene oxide)-Molten Salt Rubbery Electrolytes journal December 1994
Monte Carlo Simulations of Asymmetric Diblock Copolymer Thin Films Confined between Two Homogeneous Surfaces journal May 2001
Interfacial Interaction Dependence of Microdomain Orientation in Diblock Copolymer Thin Films journal April 2005
Mechanism of Ion Transport in Amorphous Poly(ethylene oxide)/LiTFSI from Molecular Dynamics Simulations journal February 2006
Effect of Molecular Weight on the Mechanical and Electrical Properties of Block Copolymer Electrolytes journal June 2007
Effect of Nanoscale Morphology on the Conductivity of Polymerized Ionic Liquid Block Copolymers journal July 2011
Ionic Conductivities of Block Copolymer Electrolytes with Various Conducting Pathways: Sample Preparation and Processing Considerations journal May 2012
Ionic Conductivity of Low Molecular Weight Block Copolymer Electrolytes journal January 2013
Charge Transport in Nanostructured PS–PEO–PS Triblock Copolymer Electrolytes journal April 2014
Effect of Grain Size on the Ionic Conductivity of a Block Copolymer Electrolyte journal July 2014
Effect of Tapering on Morphology and Interfacial Behavior of Diblock Copolymers from Molecular Dynamics Simulations journal July 2015
Salt Doping in PEO-Containing Block Copolymers: Counterion and Concentration Effects journal April 2009
Effect of Molecular Weight and Salt Concentration on Conductivity of Block Copolymer Electrolytes journal July 2009
On the Composition of the Top Layer of Microphase Separated Thin PS-PEO Films journal July 2009
Anisotropic Proton Conduction in Aligned Block Copolymer Electrolyte Membranes at Equilibrium with Humid Air journal January 2010
Unifying Weak- and Strong-Segregation Block Copolymer Theories journal January 1996
On the Interfacial Width in Triblock versus Diblock Copolymers:  A Neutron Reflectivity Investigation journal September 1998
Determination of Lithium-Ion Distributions in Nanostructured Block Polymer Electrolyte Thin Films by X-ray Photoelectron Spectroscopy Depth Profiling journal December 2014
Controlled ionic conductivity via tapered block polymer electrolytes journal January 2015
Nanothin film conductivity measurements reveal interfacial influence on ion transport in polymer electrolytes journal January 2019
Decoupling segmental relaxation and ionic conductivity for lithium-ion polymer electrolytes journal January 2019
Salt-doped block copolymers: ion distribution, domain spacing and effective χ parameter journal January 2012
The morphology of symmetric diblock copolymers as revealed by neutron reflectivity journal May 1990
Hyperbolic tangent variational approximation for interfacial profiles of binary polymer blends journal September 1995
Arrhenius-type temperature dependence of the segmental relaxation below Tg journal June 1999
Probing-models for interdigitated electrode systems with ferroelectric thin films journal April 2018
Ion Correlation Effects in Salt-Doped Block Copolymers journal March 2018
Rubbery Block Copolymer Electrolytes for Solid-State Rechargeable Lithium Batteries journal January 1999
Interrogation of Electrochemical Properties of Polymer Electrolyte Thin Films with Interdigitated Electrodes journal January 2018