Nafion coated sulfur–carbon electrode for high performance lithium–sulfur batteries

• Nafion coated electrode was prepared by coating nafion solution on the surface.
• Nafion membrane could be formed after thoroughly dried.
• Nafion film has the advantages of cation conductivity and anion inconductivity.
• The applicability of nafion membrane in Li–S battery was confirmed.
• The electrochemical performance of Li–S battery has been greatly improved.

In this paper, a nafion coated electrode is prepared to improve the performance of lithium sulfur batteries. It is demonstrated from a series of measurements that the nafion layer is quite effective in reducing shuttle effect and enhancing the stability and the reversibility of the electrode. When measured under the rate of 0.2 C, the initial discharge capacity of the nafion coated electrode can reach 1084 mAh g−1, with a Columbic efficiency of about 100%. After 100 charge/discharge cycles, this electrode can also deliver a reversible capacity of as high as 879 mAh g−1. Significantly, the charge-transfer resistance of the electrode tends to be reducing after coated with an appropriate thickness of nafion film. The cation conductivity as well as anion inconductivity is considered to be the dominant factor for the superior electrochemical properties.