Enabling high-performance sodium metal anodes via A sodiophilic structure constructed by hierarchical Sb2MoO6 microspheres

Sodium (Na) metal batteries have gained extensive attention as promising next-generation rechargeable batteries owing to the low cost of Na resource, high specific capacity and low electrochemical potential of Na metal anode. However, the development of Na metal batteries is still hindered by the challenge of repetitive breakage/recovery of solid electrolyte interphase (SEI) film caused by the volume expansion of Na metal anode during stripping/plating process, which results in dendritic Na growth, low Coulombic efficiency, and short cycling life. Herein, we synthesized hierarchical Sb2MoO6 (SMO) microspheres to serve as a substrate that can self-construct into a unique sodiophilic structure composed of ‘seed-embedded conductive buffer matrix’ to enable uniform Na deposition without dendrite growth. As a result, symmetric cells with Na-predeposited SMO (Na/SMO) electrodes demonstrate highly stable voltage profile with small hysteresis, excellent cycling stability (up to 500 cycles) at a high current density (up to 10 mA cm−2) and a large areal capacity (up to 8 mAh cm−2). Na-ion full cells consist of Na/SMO anode and Na3V2(PO4)3 cathode show significantly enhanced electrochemical performance (a capacity of 101.3 mAh g−1 is retained after 800 cycles at 10C) compared to the cells with bare Na metal anode.