Lithium–sulfur (Li–S) batteries are emerging as promising next‐generation chemistry due to their ultra‐high energy density, potential for improved safety and the promise of secure global supply chains. Unlike conventional Li–S systems, so‐called quasi‐solid‐state (QSS) Li–S batteries employ electrolytes that sparingly solvate polysulfide species suppressing the ‘shuttle effect’ and enhancing cycling stability. However, to date the practical deployment of QSS cells has been hindered by comparatively sluggish kinetics and limited stability; furthermore, insights into the mechanism of operation of this cell type remain scarce. Here, we demonstrate improved kinetics, through the incorporation of Li 10 GeP 2 S 12 . We explore this performance enhancement by examining degradation pathways using in situ X‐ray computed tomography imaging and complimentary electrochemical techniques. We also propose a concise methodology to quantify the sulfur intermediate according to cyclic voltammetry profiles, revealing the presence of sparingly soluble Li 2 S x ( x = 4.96) and QSS Li 2 S y ( y = 2.53) during cycling in our system. Tomographic imaging clearly identifies morphological evolution during cycling suggesting microscale changes to the electrode as a key cause of capacity decay. Protocols for electrode fabrication, electrolyte preparation, and cell assembly were established, achieving a sulfur loading > 4 mg S cm −2 , a capacity > 1200 mAh g S −1 , and stability with 2.8% capacity loss over 100 cycles.
Li et al. (Mon,) studied this question.