Understanding the operation and failure mechanism of a stable, safety-critical, electrodeposited lithium-aluminium alloy anode for lithium-sulfur batteries

The commercial application of lithium-sulfur batteries has been delayed due to problems associated with the Li metal anodes. This work fabricated a β-LiAl+α-Al composite alloy anode by electrodeposition, and investigated the following three aspects: safety, LiAl||Li half-cell performance and LiAl||Sulfur full-cell performance. Diffusional lithium trapping enabled the electrode to withstand water immersion without undergoing complete reaction. There was growth of flat LiAl mounds during cycling in both cell types attributed to lithium diffusion in the LiAl electrodes, leading to the improved stability. The shifted working voltage in the LiAl||S full-cell was attributed to the higher electrode potential of LiAl, which did not affect the reaction pathway of the Li-S battery. These unexpected aspects could offer valuable guidance for future investigations into anodes with similar mechanisms of lithium storage through diffusion.