TY - JOUR
T1 - The role of LiO 2 solubility in O 2 reduction in aprotic solvents and its consequences for Li-O 2 batteries
AU - Johnson, Lee
AU - Li, Chunmei
AU - Liu, Zheng
AU - Chen, Yuhui
AU - Freunberger, Stefan A.
AU - Ashok, Praveen C.
AU - Praveen, Bavishna B.
AU - Dholakia, Kishan
AU - Tarascon, Jean Marie
AU - Bruce, Peter G.
N1 - Publisher Copyright:
© 2014 Macmillan Publishers Limited. All rights reserved.
PY - 2014/12
Y1 - 2014/12
N2 - When lithium-oxygen batteries discharge, O 2 is reduced at the cathode to form solid Li 2 O 2. Understanding the fundamental mechanism of O 2 reduction in aprotic solvents is therefore essential to realizing their technological potential. Two different models have been proposed for Li 2 O 2 formation, involving either solution or electrode surface routes. Here, we describe a single unified mechanism, which, unlike previous models, can explain O 2 reduction across the whole range of solvents and for which the two previous models are limiting cases. We observe that the solvent influences O 2 reduction through its effect on the solubility of LiO 2, or, more precisely, the free energy of the reaction LiO 2 ∗ â €...â ‡Œâ €...Li (sol) + â €‰+â €‰O 2 â (sol) â €‰+â €‰ion pairsâ €‰+â €‰higher aggregates (clusters). The unified mechanism shows that low-donor-number solvents are likely to lead to premature cell death, and that the future direction of research for lithium-oxygen batteries should focus on the search for new, stable, high-donor-number electrolytes, because they can support higher capacities and can better sustain discharge.
AB - When lithium-oxygen batteries discharge, O 2 is reduced at the cathode to form solid Li 2 O 2. Understanding the fundamental mechanism of O 2 reduction in aprotic solvents is therefore essential to realizing their technological potential. Two different models have been proposed for Li 2 O 2 formation, involving either solution or electrode surface routes. Here, we describe a single unified mechanism, which, unlike previous models, can explain O 2 reduction across the whole range of solvents and for which the two previous models are limiting cases. We observe that the solvent influences O 2 reduction through its effect on the solubility of LiO 2, or, more precisely, the free energy of the reaction LiO 2 ∗ â €...â ‡Œâ €...Li (sol) + â €‰+â €‰O 2 â (sol) â €‰+â €‰ion pairsâ €‰+â €‰higher aggregates (clusters). The unified mechanism shows that low-donor-number solvents are likely to lead to premature cell death, and that the future direction of research for lithium-oxygen batteries should focus on the search for new, stable, high-donor-number electrolytes, because they can support higher capacities and can better sustain discharge.
UR - http://www.scopus.com/inward/record.url?scp=84911463465&partnerID=8YFLogxK
U2 - 10.1038/nchem.2101
DO - 10.1038/nchem.2101
M3 - 文章
AN - SCOPUS:84911463465
SN - 1755-4330
VL - 6
SP - 1091
EP - 1099
JO - Nature Chemistry
JF - Nature Chemistry
IS - 12
ER -