Mesoscale Elucidation of Surface Passivation in the Li–Sulfur Battery Cathode

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• 作者：Zhixiao Liu ; Partha P. Mukherjee
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：9
• 期：6
• 页码：5263-5271
• 全文大小：566K
• ISSN：1944-8252

文摘

The cathode surface passivation caused by Li₂S precipitation adversely affects the performance of lithium–sulfur (Li–S) batteries. Li₂S precipitation is a complicated mesoscale process involving adsorption, desorption and diffusion kinetics, which are affected profoundly by the reactant concentration and operating temperature. In this work, a mesoscale interfacial model is presented to study the growth of Li₂S film on carbon cathode surface. Li₂S film growth experiences nucleation, isolated Li₂S island growth and island coalescence. The slow adsorption rate at small S^2– concentration inhibits the formation of nucleation seeds and the lateral growth of Li₂S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Li₂S nucleation seeds form in such an operating temperature range, thereby facilitating heterogeneous growth and potentially inhibiting the lateral growth of the Li₂S film, which may ultimately result in reduced surface passivation. The high specific surface area of the cathode microstructure is expected to mitigate the surface passivation.