Molybdenum sulfide (MoS₂) is a prospective anode material for potassium-ion batteries, owing to its large interlayer spacing and superior theoretical capacity. Nevertheless, its practical application is hindered by sluggish kinetics and inferior structural stability, which limit its potassium storage performance. Herein, we employ hollow hard-soft carbon bowls (HSCB), consisting of soft carbon uniformly coated on hard carbon bowls, as nanoreactors to confine few-layered MoS₂ nanosheets. The mesoporous carbon shells of HSCB enhance electrolyte penetration and enable rapid charge transfer and robust structural protection, while the mechanical coupling induced by pore filling, alongside the exist of CSMo chemical bonds, further reinforces the structural integrity of MoS₂. Additionally, the creation of few-layered MoS₂ structures and MoS₂/carbon heterostructures promotes efficient K-ion adsorption and diffusion. Notably, there is a strong linear relationship between MoS₂ content and electrochemical performance, including initial Coulomb efficiency, rate performance, and reaction kinetics. Consequently, the optimized MoS₂/HSCB anode demonstrating a superior reversible capacity of 630 mAh g⁻¹ at 0.1 A g⁻¹, an exceptional rate capacity of 251 mAh g⁻¹ at 10 A g⁻¹, and excellent cycling stability, retaining 369 mAh g⁻¹ at 0.5 A g⁻¹ after 700 cycles. Remarkably, a potassium-ion hybrid capacitor assembled with MoS₂/HSCB anode achieves superior energy/power densities of 122 Wh kg⁻¹/11266 W kg⁻¹, along with splendid capacity retention of 89.5 % after 5000 cycles. This work not only offers an innovative approach for the structural engineering of high-performance sulfide-based composite materials but also elucidates the impact of sulfide content on electrochemical performance.

中文翻译：

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优化的几层 MoS2 通过孔隙填充和化学键限制在碳碗中，可实现高速钾储存的快速动力学


硫化钼 （MoS₂） 由于其层间距大和卓越的理论容量，是一种有前景的钾离子电池负极材料。然而，其实际应用受到动力学缓慢和结构稳定性差的阻碍，限制了其储钾性能。在此，我们采用空心硬软碳碗 （HSCB），由均匀涂布在硬碳碗上的软碳组成，作为纳米反应器来限制少层 MoS₂ 纳米片。HSCB 的介孔碳壳增强了电解质的渗透性，实现了快速电荷转移和强大的结构保护，而孔隙填充引起的机械耦合，以及 C S Mo 化学键的存在，进一步增强了 MoS₂ 的结构完整性。此外，少层 MoS₂ 结构和 MoS₂/碳异质结构的产生促进了 K 离子的高效吸附和扩散。值得注意的是，MoS₂ 含量与电化学性能之间存在很强的线性关系，包括初始库仑效率、倍率性能和反应动力学。因此，优化的 MoS₂/HSCB 阳极在 0.1 A ^g-1 时表现出 630 mAh ^g-1 的卓越可逆容量，在 10 A ^g-1 时具有 251 mAh ^g-1 的出色倍率容量，以及出色的循环稳定性，在 700 次循环后在 0.5 A ^g-1 下保持 369 mAh ^g-1。值得注意的是，与 MoS₂/HSCB 阳极组装的钾离子混合电容器实现了 122 Wh ^kg-1/11266 W ^kg-1 的卓越能量/功率密度，以及 89 的出色容量保持率。5 次循环后 5000 %。这项工作不仅为高性能硫化物基复合材料的结构工程提供了一种创新方法，而且还阐明了硫化物含量对电化学性能的影响。