Mirror Plane Effect of Magnetoplumbite-Type Oxide Restraining Long-Chain Polysulfides Disproportionation for High...

A facile solid-state approach is employed to synthesize a novel magnetoplumbite-type oxide of NdMgAl₁₁O₁₉, which integrates spinel-stacking layers (MgAl₂O₄) with Nd-O₆ mirror plane structures. The resulting NdMgAl₁₁O₁₉ exhibits remarkable catalytic activity and conversion efficiency during the sulfur reduction reaction (SRR) in lithium-sulfur batteries. By employing the 2D projection mapping technique of in situ confocal Raman spectroscopy and electrochemical technique, it is discovered that the exposed mirror plane structure of Nd-O₆ can effectively suppress the undesiring disproportionation reaction (S₈ ^2-→S₆ ^2-+1/4 S₈) of long-chain lithium polysulfides at the initial stages of sulfur reduction, thereby promoting the positive process of sulfur to lithium sulfide. This not only mitigates the issue of sulfur shuttle loss but also significantly improve the kinetics of the conversion process. Leveraging these advantages, the NdMgAl₁₁O₁₉/S cathode delivered an impressive initial capacity of up to 1398 mAh g^-1 at an electrolyte/sulfur (E/S) ratio of 5.1 µL mg^-1 and a sulfur loading of 2.3 mg cm^-2. Even when the sulfur loading is increased to 10.02 mg cm^-2, the cathode retained a reversible areal capacity of 10.01 mAh cm^-2 after 200 cycles. This mirror engineering strategy provides valuable and universal insights into enhancing the efficiency of cathodes in Li-S battery.