Sulfur defect engineering controls Li<sub>2</sub>S crystal orientation towards dendrite-free lithium metal batteries.

Lin, Jin-Xia; Dai, Peng; Hu, Sheng-Nan; Zhou, Shiyuan; Park, Gyeong-Su; Shi, Chen-Guang; Shen, Jun-Fei; Xie, Yu-Xiang et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Controlling nucleation and growth of Li is crucial to avoid dendrite formation for practical applications of lithium metal batteries. Li<sub>2</sub>S has been exemplified to promote Li transport, but its crystal orientation significantly influences the Li deposition behaviors. Here, we investigate the interactions between Li and various surface structures of Li<sub>2</sub>S, and reveal that the Li<sub>2</sub>S(111) plane exhibits the highest Li affinity and the lowest diffusion barrier, leading to dense Li deposition. Using sulfur defect engineering for Li<sub>2</sub>S crystal orientation control, we construct three-dimensional vertically oriented Li<sub>2</sub>S(111)@Cu nanorod arrays as a Li metal electrode substrate and identify a substrate-dependent Li nucleation process and a facet-dependent growth mode. Furthermore, we demonstrate the versatility of the Li<sub>2</sub>S(111)@Cu substrate when paired with two positive electrodes: achieving an initial discharge capacity of 138.8 mAh g<sup>-1</sup> with 88% capacity retention after 400 cycles at 83.5 mA g<sup>-1</sup> with LiFePO<sub>4</sub>, and an initial discharge capacity of 181 mAh g<sup>-1</sup> with 80% capacity retention after 160 cycles at 60 mA g<sup>-1</sup> with commercial LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> positive electrode (4 mAh cm<sup>-2</sup>).