Synergistic Capture and Conversion of Soluble Polysulfides in Li–S Batteries with Composite Freestanding Carbonaceous Interlayers

Lithium–sulfur (Li–S) batteries are considered promising next-generation energy storage systems due to their high energy density and low cost. However, their practical application still faces challenges such as the “shuttle effect” caused by polysulfides (LiPS). In this work, we use environmentally friendly bacterial cellulose (BC) as the substrate and prepare a flexible Ni-containing coordination polymer-modified carbonized BC interlayer (Ni-CBC). The combined electrochemical theoretical analysis shows that Ni-CBC not only captures LiPS effectively but also facilitates the electrochemical conversion of the adsorbed LiPS. As a result of these favorable features, the battery with the Ni-CBC interlayer delivers a stable discharge performance at 0.2C during long charge–discharge cycles and a high rate capacity of 852 mAh g–1 at 2C. This work suggests that cellulose-based materials with tailored functionality can improve the performance of Li–S batteries.