Dendrite-Free High-Capacity Alkali Metal Batteries by Two-Dimensional Confinement of Desolvated Ions

Alkali metal anodes (Li, Na, and K) hold great promise for energy storage due to their high specific capacities and low reduction potentials. However, the deposition of alkali metals is frequently disrupted by a simultaneous desolvation process, leading to dendrite growth and rapid capacity decay. In this work, we present a general strategy to achieve dendrite-free, high-capacity alkali metal batteries by utilizing the two-dimensional (2D) confinement of desolvated ions. 2D transition metal disulfides (TMDSs) are employed as interlayers with high adsorption energy for alkali metal ions, effectively facilitating the rapid separation of the desolvation process from metal deposition. The desolvated ions, characterized by high diffusivity, are confined within the 2D channels of TMDSs, enabling planar alkali metal deposition without interference from the desolvation process. Furthermore, the TMDS interlayers avoid side reactions between solvents and metals during deposition, resulting in a thin solid electrolyte interphase that promotes fast ion diffusion. This approach enables dendrite-free K metal batteries capable of plating/stripping at 10 mAh cm^-2 and cycling at 36 C for over 3000 cycles. Our strategy provides a novel pathway to advance high-energy metal batteries, significantly enhancing their performance and longevity.