All-solid-state lithium metal batteries (ASSLBs) offer an alternative route to safe and high energy density power sources. Sulfur-based cathodes with high theoretical specific capacity and low cost are crucial for advancing ASSLBs. However, the electronic insulation and sluggish kinetics of sulfide materials like Li₂S severely limit battery performance. Herein, the strategy is proposed that a highly electronic conductive Li₂S-NbSe₂ material enhances the electrochemical performance through bidirectional self-activation. The chemical interaction between Li₂S and NbSe₂ induces NbSe_2-xS_x and Li₂Se derivatization, serving as the basis for activation. The carrier transport properties, chemical evolution and self-activation mechanism of Li₂S-NbSe₂ during the oxidation–reduction process are revealed. The chemical activation of NbSe_2-xS_x is explored to accelerate the electrochemical processes by modifying the conductivity of sulfur species and the conversion pathways without insulating Li₂S and S aggregation. Therefore, ASSLBs using Li₂S-NbSe₂ as cathode active material achieve an electrode-level energy density of 394 Wh kg⁻¹ and a power density of 524 W kg⁻¹ at 1 C (4.35 mA cm⁻²) and 25 °C. The capacity retention after 100 cycles at 0.5 C is ≈99.3% with almost no degradation. This work provides new options and insights for the rational design and development of chalcogenide cathode active materials for high-performance ASSLBs.

中文翻译：

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高性能全固态锂金属电池具有双向自活化能力的导电 Li2S-NbSe2 正极材料


全固态锂金属电池 （ASSLB） 为安全和高能量密度的电源提供了另一种途径。具有高理论比容量和低成本的硫基阴极对于推进 ASSLB 至关重要。然而，Li₂S 等硫化物材料的电子绝缘和缓慢的动力学严重限制了电池的性能。在此，提出了一种策略，即一种高电子导电的 Li₂S-NbSe₂ 材料通过双向自活化来增强电化学性能。Li₂S 和 NbSe₂ 之间的化学相互作用诱导 NbSe_2-xS_x 和 Li₂Se 衍生化，作为活化的基础。揭示了 Li₂S-NbSe₂ 在氧化还原过程中的载流子传输特性、化学演变和自活化机制。探索了 NbSe_2-xS_x 的化学活化，通过改变硫物质的电导率和转化途径而不绝缘 Li₂S 和 S 聚集来加速电化学过程。因此，使用 Li₂S-NbSe₂ 作为阴极活性材料的 ASSLB 在 1 C （4.35 mA ^cm-2） 和 25 °C 时可实现 394 Wh ^kg-1 的电极级能量密度和 524 W ^kg-1 的功率密度。 在 0.5 C 下循环 100 次后，容量保持率为 ≈99.3%，几乎没有退化。这项工作为高性能 ASSLB 硫属化物正极活性材料的合理设计和开发提供了新的选择和见解。