Nafion/Titanium Dioxide-Coated Lithium Anode for Stable Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have shown great potential as high energy-storage devices. However, the stability of the Li metal anode is still a major concern. This is due to the formation of lithium dendrites and severe side reactions with polysulfide intermediates. We herein develop an anode protection method by coating a Nafion/TiO2 composite layer on the Li anode to solve these problems. In this architecture, Nafion suppresses the growth of Li dendrites, protects the Li anode, and prevents side reactions between polysulfides and the Li anode. Moreover, doped TiO2 further improves the ionic conductivity and mechanical properties of the Nafion membrane. Li-S batteries with a Nafion/TiO2 -coated Li anode exhibit better cycling stability (776 mA h g-1 after 100 cycles at 0.2 C, 1 C=1672 mA g-1 ) and higher rate performance (787 mA h g-1 at 2 C) than those with a pristine Li anode. This work provides an alternative way to construct stable Li anodes for high-performance Li-S batteries.