Fig. 3: Investigation of Li2S deposition behaviors on M-PCL electrocatalysts.
In situ XRD results of (a) Fe-PCL, (b) Co-PCL, and (c) Ni-PCL. At the beginning, a peak intensity corresponding to the sulfur decreases in all M-PCL, which indicates the complete reduction of sulfur to soluble LiPS species. The magnified in situ XRD patterns of Li2S (111) crystalline peak for (d) Fe-PCL, (e) Co-PCL, and (f) Ni-PCL. For the in situ XRD analysis, each coin cell was galvanostatically tested at 167.5 mA g−1 with cut-off voltage of 1.7–3.0 V. The in situ XRD analysis was performed for initial discharge under 30 oC. g Chronoamperometry analysis results of pristine CNT and M-PCL. After the pre-discharge process at 2.2 V to completely remove the soluble LiPS species, the current corresponding to nucleation and growth of lithium sulfide was experimentally measured at 2.05 V. h The I/Im vs T/Tm curves of pristine CNT and M-PCL. The I/Im vs T/Tm curves were reproduced from the results of chronoamperometry analysis. i Ex situ SEM images of pristine CNT and M-PCL cathodes after the initial discharge process at 83.8 mA g−1 to 1.7 V with 30 oC. For the in situ XRD and ex situ SEM analysis, the areal S loading and E/S ratio were fixed to 2.0 mg cm-2 and 10 μL mg-1, respectively.
