Pore-space-partitioned MOF separator promotes high-sulfur-loading Li–S batteries with intensified rate capability and cycling life

Abstract

An elaborately modified separator capable of simultaneously blocking polysulfide shuttle and promoting Li⁺ ion transport is crucial for developing high-energy-density lithium–sulfur (Li–S) batteries with outstanding rate performance and long cycling stability. Herein, we demonstrate an intriguing pore-space-partition strategy to reconstruct the pore network and pore chemical environment of a prototype metal–organic framework (MOF), empowering it with remarkably enhanced performance as a separator coating in Li–S batteries. The finely tailored MOF has a rational pore size, large specific surface area and abundant catalytic sites, which synergistically facilitate Li⁺ ion conduction, inhibit polysulfide shuttle, and boost catalytic polysulfide conversion, thereby realizing both outstanding rate capability and cycling stability in high sulfur loading cathodes. The as-developed cell exhibits superb cyclability with a capacity retention of 79.0% over 500 cycles. More impressively, steady cyclability and a high areal capacity of 3.96 mA h cm⁻² are achieved at a current density of up to 3.1 mA cm⁻² with 78 wt% high sulfur content. This work provides new insights into separator engineering for high-performance Li–S batteries, and would advance the development of MOF separators in various energy storage technologies.