Enhanced LiMn₂O₄Thin-Film Electrode Stability in Ionic Liquid Electrolyte: A Pathway to Suppress Mn Dissolution

TY - JOUR

T1 - Enhanced LiMn2O4Thin-Film Electrode Stability in Ionic Liquid Electrolyte

T2 - A Pathway to Suppress Mn Dissolution

AU - Torres-Castanedo, Carlos G.

AU - Evmenenko, Guennadi

AU - Luu, Norman S.

AU - Das, Paul Masih

AU - Hyun, Woo Jin

AU - Park, Kyu Young

AU - Dravid, Vinayak P.

AU - Hersam, Mark C.

AU - Bedzyk, Michael J.

N1 - Publisher Copyright: © 2023 American Chemical Society. All rights reserved.

PY - 2023/7/26

Y1 - 2023/7/26

N2 - Spinel-type lithium manganese oxide (LiMn2O4) cathodes suffer from severe manganese dissolution in the electrolyte, compromising the cyclic stability of LMO-based Li-ion batteries (LIBs). In addition to causing structural and morphological deterioration to the cathode, dissolved Mn ions can migrate through the electrolyte to deposit on the anode, accelerating capacity fade. Here, we examine single-crystal epitaxial LiMn2O4(111) thin-films using synchrotron in situ X-ray diffraction and reflectivity to study the structural and interfacial evolution during cycling. Cyclic voltammetry is performed in a wide range (2.5-4.3 V vs Li/Li+) to promote Mn3+formation, which enhances dissolution, for two different electrolyte systems: an imidazolium ionic liquid containing lithium bis-(trifluoromethylsulfonyl)imide (LiTFSI) and a conventional carbonate liquid electrolyte containing lithium hexafluorophosphate (LiPF6). We find exceptional stability in this voltage range for the ionic liquid electrolyte compared to the conventional electrolyte, which is attributed to the absence of Mn dissolution in the ionic liquid. X-ray reflectivity shows a negligible loss of cathode material for the films cycled in the ionic liquid electrolyte, further confirmed by inductively coupled plasma mass spectrometry and transmission electron microscopy. Conversely, a substantial loss of Mn is found when the film is cycled in the conventional electrolyte. These findings show the significant advantages of ionic liquids in suppressing Mn dissolution in LiMn2O4LIB cathodes.

AB - Spinel-type lithium manganese oxide (LiMn2O4) cathodes suffer from severe manganese dissolution in the electrolyte, compromising the cyclic stability of LMO-based Li-ion batteries (LIBs). In addition to causing structural and morphological deterioration to the cathode, dissolved Mn ions can migrate through the electrolyte to deposit on the anode, accelerating capacity fade. Here, we examine single-crystal epitaxial LiMn2O4(111) thin-films using synchrotron in situ X-ray diffraction and reflectivity to study the structural and interfacial evolution during cycling. Cyclic voltammetry is performed in a wide range (2.5-4.3 V vs Li/Li+) to promote Mn3+formation, which enhances dissolution, for two different electrolyte systems: an imidazolium ionic liquid containing lithium bis-(trifluoromethylsulfonyl)imide (LiTFSI) and a conventional carbonate liquid electrolyte containing lithium hexafluorophosphate (LiPF6). We find exceptional stability in this voltage range for the ionic liquid electrolyte compared to the conventional electrolyte, which is attributed to the absence of Mn dissolution in the ionic liquid. X-ray reflectivity shows a negligible loss of cathode material for the films cycled in the ionic liquid electrolyte, further confirmed by inductively coupled plasma mass spectrometry and transmission electron microscopy. Conversely, a substantial loss of Mn is found when the film is cycled in the conventional electrolyte. These findings show the significant advantages of ionic liquids in suppressing Mn dissolution in LiMn2O4LIB cathodes.

KW - LIB

KW - LiMnO

KW - epitaxial thin-films

KW - in situ

KW - ionic liquid

KW - manganese dissolution

UR - http://www.scopus.com/inward/record.url?scp=85165935328&partnerID=8YFLogxK

U2 - 10.1021/acsami.3c04961

DO - 10.1021/acsami.3c04961

M3 - 文章

C2 - 37434317

AN - SCOPUS:85165935328

SN - 1944-8244

VL - 15

SP - 35664

EP - 35673

JO - ACS applied materials & interfaces

JF - ACS applied materials & interfaces

IS - 29

ER -