Bifunctional Al2O3/polyacrylonitrile membrane to suppress the growth of lithium dendrites and shuttling of polysulfides in lithium-sulfur batteries

Interfacial engineering plays an important role in dynamically stabilizing the electrochemical performance of lithium-sulfur batteries (LSBs). Constructing a robust interface, e.g., using a multifunctional membrane, benefits not only for the suppression of lithium polysulfides (LiPSs) shuttling, but also for the inhibition of uncontrollable Li dendrite growth. Herein, a bifunctional membrane is fabricated with the Al2O3 nanoparticle-embedded polyacrylonitrile nanofibers (Al2O3/PAN) in a facile way as separator, which are found effective in blocking the growth of Li dendrite and the shuttling of LiPSs in LSBs. The exposed Al2O3 nanoparticles work in a responsible way to physiochemically capture the LiPSs and simultaneously let the Li ions shuttle through the PAN nanofiber network as the simulation indicated. The 3D cross-linked membrane can also block the oriented Li deposition and growth to make the symmetric Li||Li cell cycle over 1500 h without short circuit at 0.5 mA cm-2. Moreover, the LSB exhibits a reversible capacity of 2.08 mAh cm-2 at 500 mA g-1 under the sulfur loading of 3.6 mg cm-2. These results provide a doable and economy way to fabricate the robust membrane to deal effectively with the tough issues, which sheds new light on the design and optimization of high-energy-density sulfur prevailed rechargeable batteries.