Ferrocene-Derived Sulfur-Rich Cathode for High-Performance Rechargeable Lithium Batteries

Owing to abundant resources and lowcost, organic compounds ascathode materials have shown unique advantages in lithium batteries.Control of structures could open a new chapter in designing the advancedorganic cathode materials. Herein, we first report the synthesis ofthe ferrocene sulfur-rich copolymer (Fc-S), where the ring openingpolymerization of elemental sulfur takes place along the cyclopentenylof ferrocene. The Fc-S copolymer exhibits the nanosphere in whichthere is covalent binding between Fc and sulfur through the chemicaland physical effects. The Fc skeleton can accommodate the 70 wt %sulfur to form the Fc-S nanocages (Fc-70S), which can effectivelyrelieve the huge volume change of sulfur during the charge/dischargeprocess and ease dissolution and diffusion of polysulfides out ofcathode. The Li/Fc-70S cell can display the initial discharge specificcapacity of 1037.4 mAh g(-1) and long cycle life for700 cycles with the retention of 55.1% at 0.2 C. As a result, thisnovel Fc-S nanocomposite provides the approaches for the improvementof Li-S batteries and the development of advanced organic electrodematerials. A ferrocene-derived sulfur-richcathode was prepared, whichcan deliver high capacity and long cycle life for rechargeable lithiumbatteries.