Core-shell oxygen-deficient Fe 2 O 3 polyhedron serves as an efficient host for sulfur cathode.

Herein, an oxygen-defect-rich core-shell Fe 2 O 3- x @C polyhedral sulfur host was prepared, which effectively promoted electrochemical conversion and further inhibited the "shuttle effect" in lithium-sulfur (Li-S) batteries. Fe 2 O 3- x @C@S provided a high initial capacity of 1395 mA h g -1 and a low attenuation of ∼0.067% per cycle.