Solvothermal-Derived S-Doped Graphene as an Anode Material for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have attracted enormous attention in recent years due to the high abundance and low cost of sodium. However, in contrast to lithium-ion batteries, conventional graphite is unsuitable for SIB anodes because it is much more difficult to intercolate the larger Na ions into graphite layers. Therefore, it is critical to develop new anode materials for SIBs for practical use. Here, heteroatom-doped graphene with high doping levels and disordered structures is prepared using a simple and economical thermal process. The solvothermal-derived graphene shows excellent performance as an anode material for SIBs. It exhibits a high reversible capacity of 380 mAh g^-1 after 300 cycles at 100 mA g^-1, excellent rate performance 217 mAh g^-1 at 3200 mA g^-1, and superior cycling performance at 2.0 A g^-1 during 1000 cycles with negligible capacity fade.