Lithium–sulfur batteries (LSBs) have attracted wide attention, but the shuttle effect of polysulfide hinders their further practical application. Herein, we develop a new strategy to construct a Ketjen black@zeolite imidazole framework-8/polypropylene composite separator. Such a separator consists of Ketjen black (KB), zeolite imidazole framework-8 (ZIF-8) and polypropylene (PP) with a low coating load of 0.06 mg cm−2 and is denoted as KB@ZIF-8/PP. KB@ZIF-8/PP can absorb polysulfides because of the Lewis acid-base interaction between ZIF-8 and polysulfides. This interaction can reduce the dissolution of polysulfides and suppress the shuttle effect, thereby enhancing the electrochemical performance of the battery. When tested at a current density of 0.1 C, an LSB with a KB@ZIF-8/PP separator exhibits low polarization and achieves a high initial capacity of 1235.6 mAh/g and a high capacity retention rate of 59.27% after 100 cycles.

Because lithium-ion batteries cannot meet increasing demand for power density, lithium metal batteries are expected as the next generation of rechargeable batteries. As one of lithium metal batteries, lithium-sulfur (Li-S) batteries have attracted extensive attention because of their ultrahigh power density (2600 Wh kg −1 ) and low cost of sulfur. In order to overcome problems of active material loss, volume expansion and dendritic growth of Li metal in Li-S batteries, researchers have adopted several methods such as adding electrolyte additives, electrode modification and separator modification. Among them, separator modification shows significant advantages in inhibiting the shuttle effect of lithium polysulfides. This paper reviews research progress of inhibiting the shuttle effect of Li-S batteries by the means of the separator modification in recent years, including direct design of new type of separator and physical/chemical modification of separator surface. Through extensive reading and summarizing of the research results of the separator modification of Li-S batteries, we give the possible development direction of Li-S batteries at the end of the paper.