Tellurium‑terminated MXene synthesis via one‑step tellurium etching

As demand grows for high-performance sodium-ion batteries, the limits of traditional electrode materials in capacity and rate capability become more evident. Now, researchers from Sichuan University, SINANO-CAS, and Université de Toulouse, led by Prof. Zifeng Lin, Prof. Hui Shao, and Prof. Patrice Simon, have unveiled a breakthrough one-step elemental-tellurium etching strategy to produce Te-terminated MXenes. This work opens a scalable, fluoride-free route to next-generation 2D materials with superior sodium-storage properties.

Why Te-Terminated MXenes Matter

• Extraordinary Capacity: V₂CTe_x delivers 247 mAh g^-1 at 0.05 A g^-1 and retains 216 mAh g^-1 at a 23 C rate—>50 % higher than conventional Cl-, Br-, or F-terminated MXenes.
• Long-Life Cycling: >90 % capacity retention after 1 000 cycles at 0.1 A g^-1, enabled by stable Na–Te alloying confined on 2D scaffolds.
• Eco-Friendly & Scalable: Elemental Te etching eliminates toxic HF, operates at 700 °C under Ar, and is demonstrated on 20 g batches with 77 % yield and full Te recyclability.

Innovative Design and Features

• One-Step Redox Chemistry: Liquid Te selectively removes Al from MAX phases while grafting Te termini in situ, expanding interlayer spacing to 12.6 Å and preserving high electrical conductivity (45 S m^-1).
• Universal MAX Compatibility: Successful etching of Ti-, V-, Nb-, Ta-, Cr-, Zr-based MAX phases (211, 312, 413 types) producing accordion-like MXenes with tunable surface chemistry.
• Mechanistic Insight: DFT shows strong Te adsorption on Al sites (−2.63 eV) driving Al₂Te₃ formation; Na preferentially bonds to surface Te vacancies, combining 2D ion channels with chalcogenide alloying for fast, stable storage.

Applications and Future Outlook

• Sodium-Ion Batteries: Te-MXene anodes exhibit high-rate capability (5 A g^-1) and low polarization, enabling full cells with 104 mAh g^-1 at 0.1 A g^-1.
• Beyond Na-Ion: The elemental-etching concept (Te/Se/S/P) offers a versatile toolbox to tailor MXene terminations for Li-, K-, Zn-, and multivalent-ion systems.
• Sustainability: Te is recoverable via electrochemical reduction, positioning the process for closed-loop manufacturing.

This comprehensive study redefines MXene synthesis by merging controllable surface functionalization with green chemistry, delivering electrode materials that push sodium-ion technology toward higher energy and power densities. Stay tuned for more cutting-edge advances from Prof. Lin, Prof. Shao, and Prof. Simon’s teams!