A Na ₂ Te/Zn/Mn Framework for Achieving 100% Depth of Discharge and Realizing Ultra-Low-Excess Na Metal Batteries

Sodium metal anodes (SMAs) are promising for next-generation high-energy density batteries, but their practical application is hindered by poor ionic conductivity within the bulk anode, unstable solid electrolyte interphases (SEIs), structural degradation during cycling, and limited sodiophilicity. Here, a reconstructed SMA (Na@Na₂Te/ZM) composed of Na₂Te, Zn, and Mn within bulk Na is developed to stabilize ultrathin SMAs. Na₂Te serves as an active ion-conducting network, facilitating uniform Na⁺ transport and suppressing electron tunneling, thereby stabilizing the SEI. Mn enhances the mechanical robustness of the anode, and Zn forms a sodiophilic NaZn₁₃ alloy during initial cycling, promoting uniform Na nucleation and deposition. As a result, Na@Na₂Te/ZM anode achieves stable Na plating/stripping for nearly 1 year (over 8500 h) with a low overpotential (∼19 mV), significantly outperforming single-metal counterparts. When paired with Na₃V₂(PO₄)₃ (NVP) cathode, the full cell exhibits exceptionally high rate capability, delivering 68.5 mAh g⁻¹ at 35 C over 4000 cycles. More importantly, the modified anode allows 100% depth of discharge (DOD) at 15 mAh cm⁻² with 1 mA cm⁻², maintaining a Coulombic efficiency (CE) of 99.65% over a stable 1000 h, clearly demonstrating its potential as an efficient current collector for anode-free sodium batteries. In a limited-anode full-cell configuration with NVP, the Na₂Te/ZM framework acts as a highly effective current collector, achieving 107 mAh g⁻¹ over 300 cycles at 0.5 C. This work presents a unified, scalable strategy for advancing both durable SMAs and anode-less prototype sodium batteries.