Tailoring Electrode-Electrolyte Interfaces in Lithium-Ion Batteries Using Molecularly Engineered Functional Polymers

Laisuo Su; Jamie L Weaver; Mitchell Groenenboom; Nathan Nakamura; Eric Rus; Priyanka Anand; Shikhar Krishn Jha; John S Okasinski; Joseph A Dura; B Reeja-Jayan

doi:10.1021/acsami.0c20978

Tailoring Electrode-Electrolyte Interfaces in Lithium-Ion Batteries Using Molecularly Engineered Functional Polymers

ACS Appl Mater Interfaces. 2021 Mar 3;13(8):9919-9931. doi: 10.1021/acsami.0c20978. Epub 2021 Feb 22.

Authors

Affiliations

¹ Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
² National Institute of Standards and Technology, Material Measurement Laboratory Gaithersburg, Maryland 20899, United States.
³ National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, Maryland 20899, United States.
⁴ Department of Materials Science & Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
⁵ Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.

PMID: 33616383
DOI: 10.1021/acsami.0c20978

Abstract

Electrode-electrolyte interfaces (EEIs) affect the rate capability, cycling stability, and thermal safety of lithium-ion batteries (LIBs). Designing stable EEIs with fast Li⁺ transport is crucial for developing advanced LIBs. Here, we study Li⁺ kinetics at EEIs tailored by three nanoscale polymer thin films via chemical vapor deposition (CVD) polymerization. Small binding energy with Li⁺ and the presence of sufficient binding sites for Li⁺ allow poly(3,4-ethylenedioxythiophene) (PEDOT) based artificial coatings to enable fast charging of LiCoO₂. Operando synchrotron X-ray diffraction experiments suggest that the superior Li⁺ transport property in PEDOT further improves current homogeneity in the LiCoO₂ electrode during cycling. PEDOT also forms chemical bonds with LiCoO₂, which reduces Co dissolution and inhibits electrolyte decomposition. As a result, the LiCoO₂ 4.5 V cycle life tested at C/2 increases over 1700% after PEDOT coating. In comparison, the other two polymer coatings show undesirable effects on LiCoO₂ performance. These insights provide us with rules for selecting/designing polymers to engineer EEIs in advanced LIBs.

Keywords: LiCoO2; chemical vapor deposition polymerization; density functional theory calculation; electrode−electrolyte interface; lithium-ion batteries; poly(3,4-ethylenedioxythiophene); surface engineering; synchrotron X-ray characterization.