Modeling Analysis on Effect of Reaction Rate on Discharge Performance for Lithium-Sulfur Battery
Lithium-sulfur battery is an important candidate for the next generation of high energy density secondary batteries,and its performance improvement requires a deep understanding of the complex macroscopic electrochemical reaction processes between lithium and sulfur in the battery.In this paper, based on the Newman porous electrode model idea, combined with the typical characteristics of porous sulfur cathode, discharge process model of lithium-sulfur battery was established by reasonable simplification. The comparison of the experimental data and the discharge curve calculated by the model showed that the simulation results could basically represent the trend and key features, and validity of the model was verified. Otherwise,the simulation of discharge results under different electrochemical kinetic parameters showed that increasing the exchange reaction rate of lithium cathode oxidation was beneficial to improve the performance. For positive sulfur multi-step electrochemical reaction process,S8(l) reduction reaction rate need be maintained at a high level,S82- and S62- reduction reaction rates were not control step of multi-step electrochemical reaction, and increasing the S42- and S22- reduction reaction rates could improve the specific capacity performance and power performance of the cell.
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