Lightweight Freestanding CeF₃ Nanorod/Carbon Nanotube Composite Interlayer for Lithium–Sulfur Batteries

Although the lithium–sulfur battery has been developed for many years, how to restrain the intrinsic polysulfide shuttle is still a hot topic. Recently, it has been found that adding a multifunctional interlayer between cathode and separator can effectively inhibit the shuttle of polysulfides, while the lightweight factor of the interlayer commonly is ignored. In this work, a kind of lightly freestanding interlayer (0.16–0.4 mg cm–3) consisting of CeF3 nanorod (prepared by in situ fluorination of CeO2 nanorod in carbonization at 700 °C) and carbon nanotubes film (CF) is prepared. In this network structure, the CF network displays high electronic conduction and enhances the reaction kinetics for sulfur; CeF3 can effectively adsorb polysulfides and enhance the cycle performance. Especially, the battery exhibits an initial specific capacity of 1505 mAh g–1 at 0.05 C, and the capacity decay after 100 cycles is only 0.063% per cycle. In addition, it retains a discharge capacity of 951 mAh g–1 over 100 cycles at 0.2 C and 542 mAh g–1 over 500 cycles at 1 C. Lightly freestanding CeF3/CNTs interlayer show a high application potential in the lithium–sulfur batteries.