Among the candidates to replace Li-ion batteries, Li–S cells are an attractive option as their energy density is about five times higher (~2,600 Wh kg⁻¹). The success of Li–S cells depends in large part on the utilization of metallic Li as anode material. Metallic lithium, however, is prone to grow parasitic dendrites and is highly reactive to several electrolytes; moreover, Li–S cells with metallic Li are also susceptible to polysulfides dissolution. Here, we show that ~10-nm-thick two-dimensional (2D) MoS₂ can act as a protective layer for Li-metal anodes, greatly improving the performances of Li–S batteries. In particular, we observe stable Li electrodeposition and the suppression of dendrite nucleation sites. The deposition and dissolution process of a symmetric MoS₂-coated Li-metal cell operates at a current density of 10 mA cm⁻² with low voltage hysteresis and a threefold improvement in cycle life compared with using bare Li-metal. In a Li–S full-cell configuration, using the MoS₂-coated Li as anode and a 3D carbon nanotube–sulfur cathode, we obtain a specific energy density of ~589 Wh kg⁻¹ and a Coulombic efficiency of ~98% for over 1,200 cycles at 0.5 C. Our approach could lead to the realization of high energy density and safe Li-metal-based batteries.

在替代锂离子电池的候选产品中，Li-S电池是一种有吸引力的选择，因为它们的能量密度大约高五倍（〜2,600 Wh kg ^-1）。Li-S电池的成功在很大程度上取决于金属锂作为负极材料的利用。然而，金属锂易于生成寄生树枝状晶体，并且对几种电解质具有高反应性。此外，带有金属锂的Li–S电池也容易溶解多硫化物。在这里，我们证明了厚约10纳米的二维（2D）MoS ₂可以充当锂金属阳极的保护层，从而极大地改善了锂锂电池的性能。特别是，我们观察到稳定的锂电沉积和树枝状晶核位置的抑制。对称MoS ₂的沉积和溶解过程与使用裸露的锂金属相比，涂有涂层的锂金属电池在10 mA cm ^-2的电流密度下具有低电压滞后，并且循环寿命提高了三倍。在Li-S全电池配置中，使用MoS ₂涂层的Li作为阳极和3D碳纳米管-硫阴极，我们获得了〜589 Wh kg ^-1的比能量密度和〜98％的库仑效率。在0.5 C下经过1200个循环。我们的方法可以实现高能量密度和安全的锂金属电池。