Synchronous Promotion in Sodiophilicity and Conductivity of Flexible Host via Vertical Graphene Cultivator for Longevous Sodium Metal Batteries

Abstract Sodium (Na) metal batteries are nowadays appealing due to high specific capacity and low cost. However, major caveats including severe Na dendrite growth, unstable solid electrolyte interphase formation, and poor mechanical robustness have hampered its practicability. In this report, a highly sodiophilic and conductive host harnessing hierarchical vertical graphene (VG) cultivator and Co nanoparticle/N‐doped carbon decorator (Co‐VG/CC) is designed to accommodate Na metal throughout a facile infusion route. The strong interaction between Co‐VG/CC and Na is realized by sodiophilic Co nanoparticle/N‐doped carbon hybrid, resulting in excellent structural stability of the electrode. The well‐regulated Na adsorption behavior and uniform stripping/plating mechanism is systematically investigated via theoretical simulation in harmonization with in situ/ex situ electroanalytical analysis. In consequence, as‐derived Na@Co‐VG/CC electrode effectively inhibits the dendrite formation, resulting in promising electrochemical performances in symmetric cell configuration (functioning at an elevated rate of 5.0 mA cm⁻² under 5.0 mAh cm⁻² for 280 h, delivering a high capacity of 6.0 mAh cm⁻² at 3.0 mA cm⁻² for 1000 h and maintaining an ultralong lifespan up to 2000 h). Meanwhile, assembled flexible Na metal battery full cell can sustain to work for 120 h, representing a great advance in practical energy storage applications.