An extraordinary Na-S battery enabled by a carbon nanosheet host loaded with Fe-accelerator and TiO2-inhibitor

The inexpensive room-temperature sodium-sulfur (RT Na-S) battery has attracted extensive attention due to its various potential application but is still suffering from the low utilization of sulfur, the shuttle effect and the sluggish reaction activity of sodium polysulfides (SPSs). In this work, a TiO 2 /sulfur/atomic-iron loaded carbon nanosheet cathode is designed for high performance RT Na-S battery. When the atomic iron exists, a much higher electrochemical activity of sulfur was obtained, indicating the atomic iron can accelerate the conversion of SPSs. Furthermore, the TiO 2 layer can inhibit the shuttle effect of SPSs and the side-reaction between the intermediates and carbonate electrolyte. As a result, the constructed sulfur cathode exhibits a high reversible capacity (569.9 mAh g −1 with an initial coulombic efficiency of 57.57%) at 0.1 A g −1 and outstanding cycling performance (507 mAh g −1 after 50 cycles). This work provides a new strategy for preparing high performance cathode materials for RT Na-S battery.