Tellurium-Terminated MXene Synthesis via One-Step Tellurium EtchingOA

With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale production.The compound etching approach,which relies on cationic oxidation of the A element of MAX phase precursors while anions typically adsorb onto MXene surfaces as functional groups,remains the main prevalent strategy.By contrast,synthesis methodologies utilizing elemental etching agents have been rarely reported.Here,we report a new elemental tellurium(Te)-based etching strategy for the preparation of MXene materials with tunable surface chemistry.By selectively removing the A-site element in MAX phases using Te,our approach avoids the use of toxic fluoride reagents and achieves tellurium-terminated surface groups that significantly enhance sodium storage performance.Experimental results show that Te-etched MXene delivers substantially higher capacities(exceeding 50%improvement over conventionally etched MXene)with superior rate capability,retaining high capacity at large current densities and demonstrating over 90%capacity retention after 1000 cycles.This innovative synthetic strategy provides new insight into controllable MXene preparation and performance optimization,while the as-obtained materials hold promises for high-performance sodium-ion batteries and other energy storage systems.