Synergistic adsorption and electrocatalytic effect of Mott-Schottky heterostructure-functionalized separator for lithium-sulfur batteries

The low sulfur usage, strong shuttle effect, and dilatory redox processes limit the practical application of lithium-sulfur batteries (LSBs). The method of separator modification with a unique Mott-Schottky heterostructure used in this work significantly alleviates these issues. This unique structure is synthesized by in situ polymerizing the conductive polymer polypyrrole (PPy) on the surface of Bi 2 MoO 6 nanosheets to form Bi 2 MoO 6 -PPy nanosheets. This unique heterostructure can minimize the redox energy barrier on polysulfides due to the strong adsorption effect, high catalytic activity, and built-in electric field of Bi 2 MoO 6 -PPy nanosheets. The battery demonstrates good cycling stability when assembled with the functional separator modified by Bi 2 MoO 6 -PPy nanosheets, with an ultralow capacity decay of 0.045% per cycle over 500 cycles at 2 C. Furthermore, even with a high sulfur loading (7.5 mg cm −2 ), the battery retains an areal capacity of 6.3 mA h cm −2 at 0.2 C after 80 cycles. As a result, the suggested Mott-Schottky heterostructure-based Bi2MoO6-PPy nanosheets-modified separator (Bi 2 MoO 6 -PPy@PP separator) successfully suppresses the shuttle effect, providing an effective strategy for deploying efficient LSB.