Lithium‑sulfur batteries are recognized as a strong candidate for the next generation of high capacity density batteries. However, the shuttle effect of soluble polysulfide intermediates during the charging and discharging process of lithium‑sulfur batteries leads to a rapid decrease in their electrochemical performance, thus limiting their practical applicability. In this study, the rare earth element cerium (Ce) was introduced into a bimetallic electrocatalyst to modify the separator in order to inhibit the shuttle effect for soluble polysulfide intermediates in lithium‑sulfur batteries. The CeO2/Co bimetallic electrocatalyst composite with in situ-grown carbon nanotubes (CeO2/Co/CNT) was obtained by a simple single-step high-temperature carbonization process. The strong polarity of CeO2 in CeO2/Co/CNT could trap soluble polysulfide intermediates onto the composite surface, synergizing with Co to further enhance the catalytic efficiency of soluble polysulfide intermediates into insoluble Li2S. Simultaneously, CNTs in CeO2/Co/CNT provided fast Li+ and electron transfer channels for the efficient catalytic conversion of soluble polysulfide intermediate. The initial discharge specific capacity of lithium‑sulfur batteries assembly by using CeO2/Co/CNT modified separator presented an initial discharge specific capacity of 1377.05 mAh g−1 at 0.1 C, and 676.8 mAh g−1 after 200 cycles at 1 C, demonstrating a significant performance improvement compared to blank control battery.