Interface Engineering of MOF Nanosheets for Accelerated Redox Kinetics in Lithium-Sulfur Batteries

Abstract

Modifying the separator is considered as an effective strategy for achieving high performance lithium-sulfur (Li-S) batteries. However, most modification layers are excessively thick, with catalytic active sites primarily located within the material′s interior. This configuration severely impacts Li⁺ transport and the efficient catalytic conversion of polysulfides. Therefore, there is an urgent need to develop a multifunctional separator that integrates ultrathin design, catalytic activity, and ion sieving capabilities. Herein, we successfully linked TCPP(Ni) as a secondary ligand with Zr-BTB nanosheets to create an ultra-thin separator modification layer (Zr-TCPP(Ni)) with efficient ion sieving and catalytic properties. The resultant multifunctional separators provide robust ion sieving capabilities that promote rapid Li⁺ transport and intercept polysulfides shuttling. Therefore, The Zr-TCPP(Ni)@PP cell maintains 70.0 % of its initial capacity after 600 cycles at a high rate of 3 C, while achieving an impressive areal capacity of 4.55 mA h cm⁻² even with high sulfur content of 80 wt% at 0.5 C. This work provides valuable insights for rational design of MOF interface engineering in high energy density Li-S batteries.