TY - JOUR
T1 - Chemical Synthesis of K 2 S 2 and K 2 S 3 for Probing Electrochemical Mechanisms in K-S Batteries
AU - Gu, Sichen
AU - Xiao, Neng
AU - Wu, Feng
AU - Bai, Ying
AU - Wu, Chuan
AU - Wu, Yiying
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/12/14
Y1 - 2018/12/14
N2 - Understanding the properties of polysulfide intermediates is crucial for explaining and optimizing metal-sulfur batteries. Unlike the unstable or inseparable low-order polysulfide intermediates in Li-S systems, the K-S phase diagram displays a series of stable phases of K 2 S n (n = 1, 2, 3, 4, 5, 6), which provides the accessibility of an individual polysulfide to investigate the mechanism using pure-phase polysulfides. Herein, we synthesized two key intermediate polysulfides, K 2 S 2 and K 2 S 3 , and probed their electrochemical pathways. When K 2 S 2 and K 2 S 3 are coated directly on a current collector, both species can be further reduced. However, when K 2 S 2 and K 2 S 3 are electrically isolated from the current collector, no further reduction is observed, showing the reduction occurs through a solid-state conversion pathway. Interestingly, K 2 S 2 and K 2 S 3 can be charged even when they are electrically isolated from the current collector, proving solution-mediated charging pathways. Only K 2 S is the "dead" sulfur species that cannot be charged.
AB - Understanding the properties of polysulfide intermediates is crucial for explaining and optimizing metal-sulfur batteries. Unlike the unstable or inseparable low-order polysulfide intermediates in Li-S systems, the K-S phase diagram displays a series of stable phases of K 2 S n (n = 1, 2, 3, 4, 5, 6), which provides the accessibility of an individual polysulfide to investigate the mechanism using pure-phase polysulfides. Herein, we synthesized two key intermediate polysulfides, K 2 S 2 and K 2 S 3 , and probed their electrochemical pathways. When K 2 S 2 and K 2 S 3 are coated directly on a current collector, both species can be further reduced. However, when K 2 S 2 and K 2 S 3 are electrically isolated from the current collector, no further reduction is observed, showing the reduction occurs through a solid-state conversion pathway. Interestingly, K 2 S 2 and K 2 S 3 can be charged even when they are electrically isolated from the current collector, proving solution-mediated charging pathways. Only K 2 S is the "dead" sulfur species that cannot be charged.
UR - http://www.scopus.com/inward/record.url?scp=85058799695&partnerID=8YFLogxK
U2 - 10.1021/acsenergylett.8b01719
DO - 10.1021/acsenergylett.8b01719
M3 - Article
AN - SCOPUS:85058799695
SN - 2380-8195
VL - 3
SP - 2858
EP - 2864
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 12
ER -
