| | Current Mitigation | |---------------|------------------------| | Interfacial resistance between Na metal and SONE‑071 | Atomic‑layer‑deposited (ALD) Na‑compatible interlayers (e.g., Na₃PO₄) reduce resistance to < 10 Ω cm². | | Scale‑up reproducibility of defect‑free crystals | Laser‑float‑zone process has been adapted to a continuous‐feed furnace; early trials show < 2 % batch variance. | | Long‑term sodium dendrite formation | In‑situ X‑ray tomography shows self‑healing behavior at ≤ 0.5 mA cm⁻²; ongoing studies to verify at higher currents. | | Environmental footprint of zirconium sourcing | Recycling loops under development: zirconia recovered from spent SONE‑071 can be re‑purified > 95 % efficiency. |