Metal–Organic Framework@Polyacrylonitrile-Derived Potassiophilic Nanoporous Carbon Nanofiber Paper Enables Stable Potassium Metal Anodes

Potassium (K) metal is a promising anode for potential low-cost and high-energy-density K-ion batteries. However, its application is hampered by serious dendrite growth and large volume change. Herein, a Co nanoparticle-embedded nitrogen-doped nanoporous carbon nanofiber paper is prepared by carbonizing the electrospun fiber paper of metal–organic framework (MOF) nanoparticles and polyacrylonitrile, which displays a high potassiophilicity due to the incorporation of Co nanoparticles and N doping. As a three-dimensional host, excellent electrochemical performance is demonstrated for the K metal anode with a high average Coulombic efficiency of 98.75% for 400 cycles and a long lifespan of 1300 h in symmetric cells. Furthermore, enhanced electrochemical performance with good cycling stability and rate capability is achieved in full cells that are paired with organic cathodes. Our findings highlight a promising strategy for fabricating high-performance K metal anodes using MOF-based materials.