Sulfur and Nitrogen-doped Li4Ti5O12/rGO as an Anode Material for Advanced Sodium-ion Batteries

Abstract Finding a high-performance anode material is still a large challenge for sodium-ion batteries (SIBs) since two commercial anode materials in lithium-ion batteries, graphite, and silicon exhibit very poor sodium storage performance. Li4Ti5O12 (LTO) has become a promising candidate for SIBs mainly due to its robust structural stability. However, the utilization of LTO in SIBs was greatly limited due to its inferior conductivity and ion diffusion coefficient. To solve the above problems, in this work, structural regulating and surface modification were employed simultaneously to fabricate sulfur and nitrogen-doped LTO/reduced graphene oxide (SN-LTO/rGO) through the hydrothermal method following the calcination process with thiourea. Because of the synergistic effect of the rGO network and SN-doping, the as-obtained SN-LTO/rGO sample boasts a high discharge capacity of 132.5 mAh g-1 at a current density of 100 mA g-1 when applied as an anode in SIBs. It is pointed out that under the current density of 500 mA g-1, the discharge capacity still kept 84.6 mAh g-1 after 500 cycles, and the capacity remains at 87.40% of the initial value, indicating excellent rate performance and cycle stability.