Two-dimensional Ti3C2Tx@S as cathode for room temperature sodium-sulfur batteries

Room temperature sodium-sulfur battery has special research value due to the low cost of sulfur resource and its high specific capacity. However, the cathode material of the room temperature sodium-sulfur battery mainly combines carbon materials and elemental sulfur now, and the utilization of the sulfur is low. Herein, a two-dimensional layered material Ti3C2Tx was prepared. The cathode material of Ti3C2Tx@S was prepared by a simple melting method at 155 °C, and the mass percentage of the sublimed sulfur was 55%. Then, the valence states of Ti and C were characterized by XPS after loading the sublimed sulfur. The results indicated that a part of Ti3+ turned into the Ti4+, and some C–S bonds were formed. Additionally, the electrochemical properties of Ti3C2Tx@S were studied in sodium-ion battery under ambient conditions. The battery exhibited excellent rates performance, the first discharge specific capacity was 447.0 mAh g−1, and a specific capacity of 120.0 mAh g−1 was maintained at the current density of 1000 mA g−1. In addition, Ti3C2Tx@S demonstrated excellent cycle stability in room temperature sodium-sulfur battery. In the case of a current density of 100 mA g−1, the discharge specific capacity was maintained at 150.0 mAh g−1 after 300 cycles, and the capacity retention rate was 80% from the second cycle. For the electrode, the specific capacity still remained 107.7 mAh g−1 after 150 cycles.