Through meticulous MCR deconvolution and careful cross-referencing with standard samples, our operando XAS spectra adeptly addressed the gap left by Raman's limitations in detecting polysulfides of Li2Sx (x<4), hereby referred to as pure component #3. Surprisingly, our findings in the baseline electrolyte shown in Figures unveiled that the final product is not predominantly Li2S, the anticipated outcome in the theoretical 16-electron transfer conversion from S8 to Li2S. This divergence is likely attributed to the sluggish kinetics inherent in the liquid-solid and solid-solid conversion (2nd plateau of the voltage profile). Despite reaching the discharge cutoff voltage, the SRR remains incomplete, underscoring the complexities of the process. This unexpected observation in Li-S batteries was reported elsewhere regarding the incompletion of 16-electron transformation process, highlighting the necessities for the improvement of the Li-S kinetics. However, the higher concentration of BNC does not consistently favor the sluggish kinetics of short-chain polysulfides conversion. The final reduction product (pure component #3) exhibits no significant deviation between the baseline and 0.11 M BNC-containing electrolytes as shown in Figures and, attributable to the barely changed kinetics due to the formation of hydrogen bonds of BNC elucidated in the computational chemistry and overreactions elucidated between the BNC and polysulfides. Furthermore, the 0.11 M BNCcontaining electrolyte manifests a low composition ratio of pure component #2 throughout the entire discharge process, signifying the polysulfides depletion by excessive concentration of BNC.