文摘
The cathode surface passivation caused by Lib>2b>S precipitation adversely affects the performance of lithium–sulfur (Li–S) batteries. Lib>2b>S 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 Lib>2b>S film on carbon cathode surface. Lib>2b>S film growth experiences nucleation, isolated Lib>2b>S island growth and island coalescence. The slow adsorption rate at small S2– concentration inhibits the formation of nucleation seeds and the lateral growth of Lib>2b>S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Lib>2b>S nucleation seeds form in such an operating temperature range, thereby facilitating heterogeneous growth and potentially inhibiting the lateral growth of the Lib>2b>S 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.