The team fabricated a Li₃N (lithium nitride) layer on a lithium foil anode surface by allowing one face of the foil to flow N₂ gas at a constant velocity for 2 h. The other side of the container was separated from atmosphere by water-free liquid. The result was a Li electrode with a Li₃N protective film; the thickness of the proactive layer is around 200-300 nm.

Li₃N protection layer with high Li⁺ conductivity is fabricated on the surface of Li anode by a simple and in-situ method at room temperature. As the anode of Li-S battery, the protected Li shows greatly enhanced cycle performance because of the positive factors, the high Li⁺ conductivity of Li3N, a smooth and less resistive SEI formed between Li₃N and the electrolyte, Li₃N protection layer effectively inhibiting corrosive reaction between the Li metal and lithium polysulfides and the retarding growth of Li dendrites.

The discharge capacity retains at 773 mAh g^-1 after 500 cycles with the average coulombic efficiency of 92.3% in the electrolyte without LiNO₃, while the sulfur loading of the simple sulfur cathode was 2.5-3 mg cm^-2.

—Ma et al.

Resources

• Guoqiang Ma, Zhaoyin Wen, Meifen Wu, Chen Shen, Qingsong Wang, Jun Jin and Xiangwei Wu (2014) “Lithium anode protection guided highly-stable lithium-sulfur battery” Chem. Commun. doi: 10.1039/C4CC05535G