Constructing resilient solid electrolyte interphases on carbon nanofiber film for advanced potassium metal anodes

Stable cycling of potassium metal anodes in classic carbonate electrolytes remains a great challenge. Three-dimensional carbon hosts have been widely adopted to address the low Coulombic efficiency and devastated dendrite growth, but a correlation between the carbon microstructure and potassium plating/stripping stability has yet to be established. Here, stark contrasted carbonization temperatures, i.e., 800 and 2800 degrees C, are applied to electrospun carbon nanofiber (CNF) films for regulating graphitization degree. The resulted CNFs demonstrate distinct stability when serving as hosts for potassium metal anodes. We reveal that the carbon microstructure has a huge impact on not only the nucleation and diffusion of the K ions but also the mechanical properties of solid electrolyte interphases (SEIs). The maximum elastic deformation energy (U), which reveals the combined effects of Young's modulus and yield strain, is utilized to reflect the capability of SEI in accommodating the electrode deformation upon K deposition. The CNFs prepared at 2800 degrees C benefit the formation of a high U-value SEI. Consequently, it exhibits a small polarization and an ultra-long life of over 2000 h at 0.5 mA cm(-2) in the carbonate electrolyte. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the impact of carbon microstructure on the stability of potassium metal anodes. Carbon nanofibers prepared at different carbonization temperatures demonstrate different performance as hosts for potassium metal anodes, with CNFs produced at 2800 degrees C showing higher stability. The research reveals that the carbon microstructure plays a crucial role in nucleation and diffusion of K ions, as well as in the mechanical properties of solid electrolyte interphases (SEIs), ultimately affecting the performance of potassium metal anodes.