A thin and multifunctional CoS@g-C3N4/Ketjen black interlayer deposited on polypropylene separator for boosting the performance of lithium-sulfur batteries

作者：Liu, Xinye; Wang, Shanxing; Duan, Huanhuan; Deng, Yuanfu^*; Chen, Guohua

来源：Journal of Colloid and Interface Science, 2022, 608: 470-481.

DOI：10.1016/j.jcis.2021.09.122

• Li-S batteries
• A thin interlayer
• Chemical adsorption
• Catalytic conversion
• Synergistic effect

The sluggish redox kinetic and shuttle effect of polysulfides still obstruct the commercial application of lithium-sulfur (Li-S) batteries. Herein, a nanocomposite consisting of well-dispersed and lamellar-like shape CoS anchored on g-C(3)N4 nanosheets (CoS@g-C3N4) is prepared firstly, and then it is integrated on a polypropylene membrane combined with little conductive Ketjen black (KB) to fabricate a multi-functional and quite thin interlayer, with a thickness of only similar to 2.1 um and areal mass loading of similar to 0.0 7 mgcm(2). The as-prepared interlayer firstly can capture polysulfides by Li-N bond as well as Lewis acid-base interaction between CoS and polysulfide anions (S-n(2-)), and more importantly, it also displays a positive effect on catalyzing the redox conversion of intermediate polysulfides. As expected, a Li-S cell assembled with this modified separator and high sulfur content cathode displays an excellent electro-chemical performance, with specific capacity of similar to 1290 mAh g(1) at 0.2C and a low fading rate of 0.03% per cycle after 500 cycles at 1.0C. Furthermore, a high sulfur mass loading of similar to 4.0 mgcm(2) elec-trode paired with this multifunctional separator exhibits a stable specific capacity of similar to 600 mAh g(1) after 250 cycles under 0.1C. This work can give some guides to rational design a quite thin and light interlayer for improving the utilization of sulfur species, with little damage to the energy density and Li ion trans-portation in Li-S batteries.