The shuttle effect caused by polysulfides remains a major issue hindering the appli-cation of lithium–sulfur (Li-S) batteries. In this work, a composite of organicallymodified carbon nanotube (CNT) and zirconia (ZrO2) nanoparticles is synthesized and used as a surface coating on a commercial Celgard separator to restrain the shuttle effect and improve battery performance. Electrolyte uptake and water con-tact angle measurements show that the CNT/ZrO2composite-coated separator has anenhanced electrolyte wettability. Thermal shrinkage results reveal an improvement inthe stability of the coated separators, especially at high temperatures. Electrochemical measurements also show the effectiveness of the CNT/ZrO2composite-coatedseparator in a Li–S battery. The initial discharge capacity is improved after coating,as is the capacity retention rate. In addition, a battery with a CNT/ZrO2composite-coated separator attains an impressive capacity reversibility as high as 91.7% in a rate performance test from 0.1 to 2 C. The composite coating restrains the shuttle effect effectively and improves the thermal shrinkage properties of the separator. Thus, the use of a CNT/ZrO2composite-coated separator should improve the prospects for practical application of Li–S batteries