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Abstract MXenes have emerged as promising candidates for hosting sulfur in lithium-sulfur (Li-S) batteries due to their exceptional electrical conductivity. Despite recognition of the significant influence of functional groups on the MXene surface on sulfur conversion reactions, a clear experimental understanding remains elusive. This study unveils that Ti3C2 MXene functionalized with –S groups demonstrates superior capabilities in anchoring and catalyzing lithium polysulfides (LiPSs) compared to counterparts functionalized with –Cl and –F groups. The Ti3C2S2 MXene is synthesized via the molten salt method, followed by functional group replacement. Ti3C2S2 MXene exhibits robust chemisorption strength, effectively mitigating LiPS dissolution and shuttling. Additionally, it demonstrates remarkable electrocatalytic prowess for Li2S deposition/decomposition, thereby enhancing reaction kinetics. As a result, Ti3C2S2 MXene-modified separators allow Li-S cells to achieve a high capacity of 1305 mAh/g at 0.1 C, alongside excellent cyclic retention of ≈81% after 1000 cycles. Even with an S loading of 6.5 mg/cm2, it attains a notable areal capacity exceeding 5.5 mAh/cm2. This work underscores the potential of surface modification strategies in boosting the anchoring and electrocatalytic performance of Ti3C2S2 MXene in Li-S batteries.
Wang et al. (Tue,) studied this question.