Hierarchical SnS2/carbon nanotube@reduced graphene oxide composite as an anode for ultra-stable sodium-ion batteries

Abstract

Ultrathin SnS2 layers with high theoretical specific capacity displays promising advantages as an anode in sodium storage systems. However, their poor conductivity and large capacity loss during charging/discharging process are urgently needed to be addressed. Herein, an exotic hierarchical SnS2/carbon nanotube@reduced graphene oxide (SnS2/CNT@rGO) composite has been designed and developed to be an anode for sodium-ion batteries. Functionally, the CNT penetrates into the petals of SnS2 micro-flowers to increase the conductivity of SnS2, while the three-dimensional rGO wraps around the SnS2/CNT composite to relieve the volume expansion of SnS2 during the charging/discharging process and construct “rGO conductive bridge” to accelerate electrode reaction kinetics. Benefiting from these exotic functionalization, the SnS2/CNT@rGO anode possesses excellent reversible capacity and superior cycling stability with a high reversible capacity of 528 mA h g−1 at 50 mA g−1 and a retained capacity of 301 mA h g−1 after 1000 cycles at 1 A g−1, which are better than most of the previously reported Sn-based and carbon-based anode materials. This study offers a promising strategy for significantly improving the cycling stability in the ultra-stable electrode materials in sodium-ion batteries.