Dual synergistic immobilization effect on lithium polysulfides for lithium-sulfur batteries

Although lithium sulfur batteries (LSBs) possess extremely high specific capacity and ultrahigh energy density, the low conductivity and severe shuttle effect greatly restrict its practical application. Herein, we report a facile strategy to overcome the problems via a double-layer structure, in which one provides strong chemisorption by functionalized reduced graphene oxide (rGO) while the other confines polysulfides physically through coating a layer of rGO film on the electrode. The strategy not only alleviates the dissolution and diffusion of polysulfides but also inhibits polysulfides from penetrating into anode to some extent and enhances the electrical conductivity of electrode. The LSBs employing double-layer structure electrodes exhibit high initial capacity of 1353 mAh g(-1) at 0.1 C and 78% capacity retention after 100 cycles, good cycling stability with only 0.056% capacity decay per cycle at 1 C, and remarkable rate capability with 92% reversible capacity retention. The current findings manifest that the double-layer structure can effectively improve the electrochemical performance via the dual synergistic effect of both chemical interaction and physical confinement.