TY - JOUR
T1 - Solvation Structure around Li+Ions in Organic Carbonate Electrolytes
T2 - Spacer-Free Thin Cell IR Spectroscopy
AU - Lim, Chaiho
AU - Kim, Joo Hyun
AU - Chae, Yeongseok
AU - Lee, Kyung Koo
AU - Kwak, Kyungwon
AU - Cho, Minhaeng
N1 - Funding Information:
This work was supported by the Institute for Basic Science (IBS-R023-D1) (M.C.) and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2020R1A5A1019141) (K.K.)
Publisher Copyright:
© 2021 American Chemical Society
PY - 2021/9/21
Y1 - 2021/9/21
N2 - Organic carbonate electrolytes are widely used materials for lithium-ion batteries. However, detailed solvation structures and solvent coordination numbers (CNs) of lithium cations in such solutions have not been accurately described nor determined yet. Because transmission-type IR spectroscopy is not of use for measuring the carbonyl stretch modes of electrolytes due to their absorption saturation problem, we here show that simple spacer-free thin cell IR spectroscopy can provide quantitative information on the number of solvating carbonate molecules around each lithium ion. We could estimate the solvent (carbonate) CNs of lithium ions in dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and butylene carbonate over a wide range of lithium salt concentrations accurately, and they are compared with the previous results obtained with attenuated total reflection IR spectroscopy technique. We anticipate that our spacer-free thin cell approach will potentially be used to investigate the solvation dynamics, chemical exchange process, and vibrational energy transfers between solvating carbonate molecules in lithium salt electrolytes when combined with time-resolved IR spectroscopy.
AB - Organic carbonate electrolytes are widely used materials for lithium-ion batteries. However, detailed solvation structures and solvent coordination numbers (CNs) of lithium cations in such solutions have not been accurately described nor determined yet. Because transmission-type IR spectroscopy is not of use for measuring the carbonyl stretch modes of electrolytes due to their absorption saturation problem, we here show that simple spacer-free thin cell IR spectroscopy can provide quantitative information on the number of solvating carbonate molecules around each lithium ion. We could estimate the solvent (carbonate) CNs of lithium ions in dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and butylene carbonate over a wide range of lithium salt concentrations accurately, and they are compared with the previous results obtained with attenuated total reflection IR spectroscopy technique. We anticipate that our spacer-free thin cell approach will potentially be used to investigate the solvation dynamics, chemical exchange process, and vibrational energy transfers between solvating carbonate molecules in lithium salt electrolytes when combined with time-resolved IR spectroscopy.
UR - http://www.scopus.com/inward/record.url?scp=85115769863&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.1c02127
DO - 10.1021/acs.analchem.1c02127
M3 - Article
AN - SCOPUS:85115769863
VL - 93
SP - 12594
EP - 12601
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 37
ER -