Perovskite-Type CsGeI<sub>3</sub> as an Electrolyte Additive for All-Solid-State Lithium–Sulfur Batteries
Peng‐Fei Wang, Yihan Zhao, Shu-Hui Tian, Zihan Shen, Ting‐Feng Yi
Abstract
Poly(ethylene oxide) (PEO)-based solid-state lithium–sulfur (Li–S) batteries have received widespread attention for their advantages in terms of safety and high energy density. However, in practice, they still remain challenging to simultaneously realize no “shuttle effect”, high ionic conductivity, and superior stability to Li. In addressing these issues, this work proposes a novel perovskite-type additive, CsGeI 3, into the polymer electrolyte. On the one hand, the additive with a metal ion bond can adsorb the dissolved polysulfides, thereby inhibiting the “shuttle effect”. On the other hand, the additive can reduce the crystallinity of PEO, thus improving the ionic conductivity. Moreover, the additive can react with Li metal to generate a uniform and dense interface layer, which can further block the reaction of polysulfides with Li metal and optimize the Coulombic efficiency of electrodes. This polymer solid-state electrolyte exhibits excellent electrochemical performance when applied to Li–S batteries, providing a specific capacity of 1141.9 mA h g –1 at 0.2 C and maintaining stable cycling for 100 cycles with a retention rate of 72%. Overall, this work will develop a novel polymer electrolyte based on perovskite-type CsGeI 3 additives, providing a feasible solution for the practical application of a high specific energy battery system.