Atomically Dispersed Tellurium‐Enabled Highly Stable Potassium Metal Batteries

ABSTRACT Potassium metal batteries hold great promise for grid‐scale energy storage. As a typical and widely used anode, Potassium (K) metal faces challenges of an unstable solid electrolyte interphase (SEI), notorious dendritic growth, and large volume change during K plating/stripping. Herein, atomic tellurium supported on nitrogen/phosphorus‐codoped porous carbon nanofibers (TeNPC) was designed as the host for accommodating metallic K. The uniformly dispersed Te atoms serve as potassiophilic sites, which can effectively reduce the nucleation energy barrier and guide K nuclei formation and growth. The atomic Te not only allows the homogeneous distribution of the electric field but also enhances the binding energy of the host to decrease K + concentration polarization, inducing smooth K deposition. Additionally, the hierarchical pore structure of TeNPC and the formation of SEI with a KF‐rich inner layer contribute to a dendrite‐free morphology of K@TeNPC. Consequently, TeNPC enables a low nucleation overpotential (~21 mV at 0.5 mA cm –2 and 1.0 mAh cm –2 ) and high Coulombic efficiency (~99.8% after 480 cycles) for K deposition/stripping. Furthermore, K@TeNPC shows favorable rate capability and cycle life in symmetric cells and potassium–sulfur batteries. This work presents a new insight into the development of highly efficient host materials for K metal anodes.

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