TY - JOUR
T1 - Unraveling the Dynamic Interfacial Behavior of LiCoO2 at Various Voltages with Lithium Bis(oxalato)borate for Lithium-Ion Batteries
AU - Hong, Meihua
AU - Lee, Subin
AU - Ho, Van Chuong
AU - Lee, Daon
AU - Yu, Seung Ho
AU - Mun, Junyoung
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1F1A105970411). This research was supported by the Technology Innovation Program (200109000 and 20011173) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).
Publisher Copyright:
© 2022 American Chemical Society
PY - 2022/3/2
Y1 - 2022/3/2
N2 - The electrochemical dynamic behavior of the solid electrolyte interface (SEI) formed on LiCoO2 (LCO) by lithium bis(oxalato)borate (LiBOB) is investigated at various cutoff voltages. Particularly, for layered cathode active materials, various cutoff voltages are used to control the delithiation states; however, systematic investigations of the voltage and SEI are lacking. To increase the practical energy density of the LCO, a high cutoff voltage is pursued to utilize a state of high delithiation. However, this high cutoff voltage causes the electrolyte to undergo side reactions and the crystalline structure changes irreversibly, limiting the cycle life. In a low-voltage environment (<4.7 V), LiBOB improves the initial Coulombic efficiency and cycling performance by forming an effective SEI, which suppresses side reactions. At higher voltage levels (4.7-4.9 V), LiBOB no longer effectively protects the surface, causing the electrochemical performance to decrease rapidly. The main cause of this phenomenon is the decomposition of LiBOB-SEI at a high voltage, as shown by systematic surface and electrochemical analyses comprising linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. In conclusion, LiBOB can suppress side reactions of the electrolyte by SEI formation, but the SEI decomposes at voltage levels higher than 4.7 V.
AB - The electrochemical dynamic behavior of the solid electrolyte interface (SEI) formed on LiCoO2 (LCO) by lithium bis(oxalato)borate (LiBOB) is investigated at various cutoff voltages. Particularly, for layered cathode active materials, various cutoff voltages are used to control the delithiation states; however, systematic investigations of the voltage and SEI are lacking. To increase the practical energy density of the LCO, a high cutoff voltage is pursued to utilize a state of high delithiation. However, this high cutoff voltage causes the electrolyte to undergo side reactions and the crystalline structure changes irreversibly, limiting the cycle life. In a low-voltage environment (<4.7 V), LiBOB improves the initial Coulombic efficiency and cycling performance by forming an effective SEI, which suppresses side reactions. At higher voltage levels (4.7-4.9 V), LiBOB no longer effectively protects the surface, causing the electrochemical performance to decrease rapidly. The main cause of this phenomenon is the decomposition of LiBOB-SEI at a high voltage, as shown by systematic surface and electrochemical analyses comprising linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. In conclusion, LiBOB can suppress side reactions of the electrolyte by SEI formation, but the SEI decomposes at voltage levels higher than 4.7 V.
KW - high-voltage
KW - LiCoO
KW - lithium bis(oxalato)borate (LiBOB)
KW - lithium-ion batteries
KW - solid electrolyte interphase (SEI)
UR - http://www.scopus.com/inward/record.url?scp=85125681008&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c21952
DO - 10.1021/acsami.1c21952
M3 - Article
C2 - 35188752
AN - SCOPUS:85125681008
SN - 1944-8244
VL - 14
SP - 10267
EP - 10276
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 8
ER -