Prompt Molten Na Infusion and Fluidic Transport by Virtue of Versatile Nano Canal Defects on Tin Oxide Sodiophilic Hosts

Intrinsically weak metal affinity and sluggish sodium (Na) nucleation/molten fluidic transport of conventional hosts impede the fabrication of high-capacity Na anodes. Mediating surface free energies (SFEs) of hosts and reinforcing their intermolecular attraction to viscous Na fluids can radically solve these problems. Herein, “canaled” tin oxide nanorod arrays grown on a 3D carbon cloth (CC) matrix exhibit distinct polar/nonpolar SFE components that markedly elevate the solid–liquid wettability for molten Na is reported. Such nanocanal defects render strong capillary forces for spontaneous molten Na imbibition and help to instantly activate Na─Sn alloying and Na nucleation reactions. Furthermore, sodiophilic Na₁₅Sn₄ interlayers evolved in former alloying procedures also aid in reducing Na nucleation energy barriers and guide the planar electro-deposition/dispersion, alleviating the uncontrolled Na dendrite growth. The derived Na/Na₁₅Sn₄/CC anodes can thus keep stable after 2000 h of galvanostatic cycling at 1 mA cm⁻² or high-rate testing, without notable dendritic formation. The packed full cells also show superior rate capability and cyclability (capacity retention over 91.5% after all cycling at 1 C). This work provides a smart nano-engineering way to trigger a fast infusion of molten metals into hosts and synergistically facilitate Na fluidic transport, which may push forward the scalable application of Na metal batteries.