Dual chemifunctional tin(IV) oxide/nanoperforated graphene interlayer as a polysulfide adsorbent for use in high-performance lithium–sulfur batteries

Abstract

The development of Li–S batteries is limited by their levels of rapid capacity decay owing to polysulfide dissolution and diffusion in organic electrolytes. We addressed this critical issue by fabricating a dual chemifunctional interlayer comprising SnO2 nanoparticles and nanoperforated graphene (NPG) that could function as a polysulfide adsorbent. The synergistic effects of SnO2 and the high-density functional groups of NPG on polysulfide capture were conceptually confirmed. NPG not only supported the adsorption of Li polysulfides but also provided pathways for simple Li-ion motion within the SnO2/NPG interlayer. A cell assembled with the SnO2/NPG interlayer displayed a high rate capability and initial discharge capacity and good reversible capacity. The excellent high-rate cycling performance of the cathode could mainly be attributed to the strong chemical bonds formed between SnO2/NPG and the polysulfides, rapid electron transfer, and optimized ion diffusion pathways derived from the well-organized structure of the composite. Synthesizing dual chemifunctional interlayers using a composite of metal oxides and NPG may lead to the development of advanced Li–S batteries with numerous practical applications in the near future.