Solid-state potassium metal batteries have increasingly gained attention as promising alternatives in large-scale energy storage due to their safety and low cost. However, these batteries usually suffer from a lack of suitable K⁺ conducting solid electrolytes. Herein, a new KB₁₁H₁₄·2Me₃NBH₃ complex electrolyte with high ionic conductivity and relative stability against K metal is reported. The crystal structure was solved as a monoclinic P2₁/c lattice. Density functional theory (DFT) calculations confirm significantly enhanced K-ion diffusion in the structure. High K-ion conductivities of 2.63 × 10⁻⁶ S cm⁻¹ at 25 °C and 3.25 × 10⁻⁴ S cm⁻¹ at 75 °C are achieved, putting it among the leading K⁺ solid conductors. Moreover, it shows favorable interfacial stability against the K metal anode precoated with NH₃B₃H₇. Batteries coupling the TiS₂ cathode deliver long-term cycling stability. This work provides a new group of K-ion solid-state electrolytes for safe potassium metal batteries.

中文翻译：

---

由 KB11H14·2Me3NBH3 复合电解质实现的稳定固态钾金属电池


固态钾金属电池因其安全性和低成本而成为大规模储能的有前途的替代品，越来越受到关注。然而，这些电池通常缺乏合适的 K⁺ 导电固体电解质。在此，报道了一种新的 KB₁₁H₁₄·2Me₃NBH₃ 络合电解质，具有高离子电导率和对 K 金属的相对稳定性。晶体结构被求解为单斜 P2₁/c 晶格。密度泛函理论 （DFT） 计算证实了结构中 K 离子扩散的显著增强。在 25 °C 时实现了 2.63 × ^10-6 S ^cm-1 的高 K 离子电导率，在 75 °C 时实现了 3.25 × ^10-4 S ^cm-1，使其成为领先的 K⁺ 固体导体之一。此外，它对预涂有 NH₃B₃H₇ 的 K 金属阳极表现出良好的界面稳定性。耦合 TiS₂ 阴极的电池可提供长期的循环稳定性。这项工作为安全的钾金属电池提供了一组新的 K-ion 固态电解质。