Investigation of polysulfide dissolution behavior using various amine groups functionalized order mesoporous carbon as sulfur hosts in lithium‑sulfur batteries.

In this work, various amine groups (ethylenediamine; EDA, tetraethylenepentamine; TEPA and polyethylenimine; PEI) functionalized 3D body-centered cubic mesoporous carbon materials (FDU16) were prepared to host sulfur to form FDU16-EDA/S, FDU16-TEPA/S and FDU16-PEI/S cathode materials for high performance Li S batteries. The materials were characterized by XRD, SAXS, SEM, TEM, Raman, EA, BET, CV and RRDE. The results showed that FDU16-PEI/S exhibited the largest initial discharge capacity of 1266 mAg g−1 at 0.1C and presented a lower capacity fading rate of 0.26% per cycle for the 100 cycles in comparison with the capacity fading rate of FDU16/S (0.41%), FDU16-EDA/S (0.31%) and FDU16-TEPA/S (0.29%). During the RRDE experiments, all samples revealed similar RRDE profiles in all disk voltage (DV) regions, suggesting they resemble the dissolution behavior of the LiPS intermediates during the cycling process. The FDU16-PEI/S owned a smaller slope value of ring current change in the DV II region, indicating a lower dissolution of LiPS intermediates from the sulfur electrode. The order of LiPS adsorption efficiency was shown to be PEI > TEPA > EDA. This study demonstrated carbon materials functionalized with large amine groups provide strong affinities with LiPS intermediates, resulting in notably improving cycle performance in Li S batteries. [Display omitted] • FDU16 with various amine-containing functionalities as sulfur host materials were fabricated. • An in situ RRDE is designed to study polysulfide dissolution behavior in Li S batteries. • LiPS trapping capability increased with the number of amine groups (EDA < TEPA < PEI). • Functionalization of PEI with FDU16 displays the best cycling performance. [ABSTRACT FROM AUTHOR]