Interlayer-expanded MoS₂ assemblies for enhanced electrochemical storage of potassium ions

Potassium-ion batteries are regarded as the low-cost alternative to lithium-ion batteries. However, their development is hampered by the lack of suitable electrode materials. In this work, we demonstrate that MoS₂ with expanded interlayers represents a promising candidate for the electrochemical storage of potassium ions. Hierarchical interlayer-expanded MoS₂ assemblies supported on carbon nanotubes are prepared via a straightforward solution method. The increased interlayer spacing not only enables the better accommodation of foreign ions, but also lowers the diffusion energy barrier and improves diffusion kinetics of ions. When investigated as the anode material of potassium ion batteries, our interlayer-expanded MoS₂ assemblies exhibit an excellent electrochemical performance with large capacity (up to ~ 520 mAh·g^-1), good rate capability (~ 310 mAh·g^-1 at 1,000 mA·g^-1) and impressive cycling stability, superior to most competitors.