Investigation of the Li-S Battery Mechanism by Real-Time Monitoring of the Changes of Sulfur and Polysulfide Species during the Discharge and Charge.
The mechanism of the sulfur cathode in Li-S batteries has been proposed. It was revealed by the real-time quantitative determination of polysulfide species and elemental sulfur by means of high-performance liquid chromatography in the course of the discharge and recharge of a Li-S battery. A three-step reduction mechanism including two chemical equilibrium reactions was proposed for the sulfur cathode discharge. The typical two-plateau discharge curve for the sulfur cathode can be explained. A two-step oxidation mechanism for Li2S and Li2S2with a single chemical equilibrium among soluble polysulfide ions was proposed. The chemical equilibrium among S52-, S62-, S72-, and S82-throughout the entire oxidation process resulted for a single flat recharge curve in Li-S batteries.
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Dong
D
Zheng
Department of Chemistry, School of Science, Wuhan University of Technology , Wuhan 430070, Hubei, P. R. China.
Dan
D
Liu
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Joshua B
JB
Harris
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Tianyao
T
Ding
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Jingyu
J
Si
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Sergei
S
Andrew
Department of Chemistry, School of Science, Wuhan University of Technology , Wuhan 430070, Hubei, P. R. China.
Deyu
D
Qu
Chemistry Department, Brookhaven National Laboratory , Upton, New York 11973, United States.
Xiao-Qing
XQ
Yang
Department of Mechanical Engineering, College of Engineering and Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States.
Deyang
D
Qu
HPLC; Li−S battery; charge and discharge mechanisms; polysulfide and sulfur determination; polysulfide equilibrium