TY - JOUR
T1 - Li-O2 Cell with LiI(3-hydroxypropionitrile)2 as a Redox Mediator
T2 - Insight into the Working Mechanism of I- during Charge in Anhydrous Systems
AU - Li, Yang
AU - Dong, Shanmu
AU - Chen, Bingbing
AU - Lu, Chenglong
AU - Liu, Kailiang
AU - Zhang, Zhonghua
AU - Du, Huiping
AU - Wang, Xiaogang
AU - Chen, Xiao
AU - Zhou, Xinhong
AU - Cui, Guanglei
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/9/7
Y1 - 2017/9/7
N2 - Redox mediators (RMs) have been widely applied to reduce the charge overpotential of nonaqueous lithium-oxygen (Li-O2) batteries. Among the reported RMs, LiI is under hot debate with lots of controversial reports. However, there is a limited understanding of the charge mechanism of I- in anhydrous Li-O2 batteries. Here, we study the chemical reactivity between the oxidized state of I- and Li2O2. We confirm that the Li2O2 particles could be chemically oxidized by I2 rather than I3- species. Furthermore, our work demonstrates that the generated I- from Li2O2 oxidation would combine with I2 to give I3- species, hindering further oxidation of Li2O2 by I2. To improve the working efficiency of I- RMs, we introduce a compound LiI(3-hydroxypropionitrile)2 (LiI(HPN)2) with a high binding ability of I-. Compared with LiI, the cell that contained LiI(HPN)2 shows a significantly increased amount of I2 species during charge and enhanced Li2O2 oxidation efficiency under the same working conditions.
AB - Redox mediators (RMs) have been widely applied to reduce the charge overpotential of nonaqueous lithium-oxygen (Li-O2) batteries. Among the reported RMs, LiI is under hot debate with lots of controversial reports. However, there is a limited understanding of the charge mechanism of I- in anhydrous Li-O2 batteries. Here, we study the chemical reactivity between the oxidized state of I- and Li2O2. We confirm that the Li2O2 particles could be chemically oxidized by I2 rather than I3- species. Furthermore, our work demonstrates that the generated I- from Li2O2 oxidation would combine with I2 to give I3- species, hindering further oxidation of Li2O2 by I2. To improve the working efficiency of I- RMs, we introduce a compound LiI(3-hydroxypropionitrile)2 (LiI(HPN)2) with a high binding ability of I-. Compared with LiI, the cell that contained LiI(HPN)2 shows a significantly increased amount of I2 species during charge and enhanced Li2O2 oxidation efficiency under the same working conditions.
UR - http://www.scopus.com/inward/record.url?scp=85029107172&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.7b01497
DO - 10.1021/acs.jpclett.7b01497
M3 - 文章
C2 - 28825835
AN - SCOPUS:85029107172
SN - 1948-7185
VL - 8
SP - 4218
EP - 4225
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 17
ER -