Solid-state rigid-rod polymer composite electrolytes with nanocrystalline lithium ion pathways

Ying Wang; Curt J Zanelotti; Xiaoen Wang; Robert Kerr; Liyu Jin; Wang Hay Kan; Theo J Dingemans; Maria Forsyth; Louis A Madsen

doi:10.1038/s41563-021-00995-4

Solid-state rigid-rod polymer composite electrolytes with nanocrystalline lithium ion pathways

Nat Mater. 2021 Sep;20(9):1255-1263. doi: 10.1038/s41563-021-00995-4. Epub 2021 May 3.

Authors

Ying Wang¹, Curt J Zanelotti¹, Xiaoen Wang², Robert Kerr², Liyu Jin², Wang Hay Kan³, Theo J Dingemans⁴, Maria Forsyth², Louis A Madsen⁵

Affiliations

¹ Department of Chemistry and Macromolecules Innovation Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
² Institute for Frontier Materials and ARC Centre of Excellent for Electromaterials Science, Deakin University, Geelong, Victoria, Australia.
³ China Spallation Neutron Source, Chinese Academy of Science, Dongguan, China.
⁴ Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
⁵ Department of Chemistry and Macromolecules Innovation Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA. lmadsen@vt.edu.

PMID: 33941912
DOI: 10.1038/s41563-021-00995-4

Abstract

A critical challenge for next-generation lithium-based batteries lies in development of electrolytes that enable thermal safety along with the use of high-energy-density electrodes. We describe molecular ionic composite electrolytes based on an aligned liquid crystalline polymer combined with ionic liquids and concentrated Li salt. This high strength (200 MPa) and non-flammable solid electrolyte possesses outstanding Li⁺ conductivity (1 mS cm^-1 at 25 °C) and electrochemical stability (5.6 V versus Li|Li⁺) while suppressing dendrite growth and exhibiting low interfacial resistance (32 Ω cm²) and overpotentials (≤120 mV at 1 mA cm^-2) during Li symmetric cell cycling. A heterogeneous salt doping process modifies a locally ordered polymer-ion assembly to incorporate an inter-grain network filled with defective LiFSI and LiBF₄ nanocrystals, strongly enhancing Li⁺ conduction. This modular material fabrication platform shows promise for safe and high-energy-density energy storage and conversion applications, incorporating the fast transport of ceramic-like conductors with the superior flexibility of polymer electrolytes.