Shielding polysulfides enabled by a biomimetic artificial protective layer in lithium-sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries are widely considered to be next-generation storage technologies due to their high energy density, low cost and non-toxicity. However, the soluble lithium polysulfides (LiPS) migrating to the anode side inevitably causes side reactions with the Li anode, resulting in severe corrosion of the Li anode, loss of active materials, and rapid battery failure. Therefore, it is necessary to develop effective strategies to avoid LiPS exposure to Li anodes. Herein, a stable UiO-66-ClO4/PDMS (PDUO-Cl) biomimetic protective layer is rationally constructed by the drip coating method. The PDUO-Cl protective layer can effectively suppress the side reaction of Li metal with LiPSs/electrolyte and homogenize the Li+ flux, thus avoiding corrosion of the Li metal anode. As a result, the symmetric cell with the PDUO-Cl protective layer delivers a stable cycle performance greater than 1400 h under a current density of 0.5 mA cm−2. The Li–S batteries with a PDUO-Cl protective layer still show relatively better rate performance and cycling stability (69% after 100 cycles at 0.1 C). This work provides new insights into the design of protective strategies for Li anodes in Li–S batteries.