Three-dimensional carbon foam decorated with SnO2 as multifunctional host for lithium sulfur batteries

Lithium–sulfur (Li–S) batteries with high theoretical capacity and abundant sulfur resources are potential energy storage systems. Nevertheless, there are several roadblocks that strongly limit the commercial application of Li-S batteries, including the insulating nature of sulfur and Li2S, large volume change and the shuttle effect of lithium polysulfides. Herein, a three-dimensional carbon foam (CF) decorated with SnO2 (SnO2/CF) is fabricated by the simple electrodeposition and used as a sulfur host to resolve the bottleneck issues in Li-S batteries. Thanks to the synergetic effect of the polar SnO2 and conductive carbon framework, the SnO2/CF framework is endowed with multifunctionalities such as providing three-dimensional conductive framework, inhibiting the migration of polysulfides and improved reaction kinetics. Consequently, durable cycle performance with a capacity of 458.2 mAh g−1 after 1000 cycles at 1 C is achieved. Furthermore, a high capacity of 749.5 mAh g−1 at a high rate of 5 C is attained. Remarkably, under high sulfur loading of 8.84 mg cm−2, the S@SnO2/CF cathode can still deliver a high specific capacity of 389.8 mAh g−1 after 300 cycles at 0.5 C. This work demonstrates a novel strategy to improve the performance of Li-S batteries for energy storage applications.