Confining CoTe₂-ZnTe heterostructures on petal-like nitrogen-doped carbon for fast and robust sodium storage

Two-phase or multiphase engineering is contributed to realizing rapid electron/ion transfer kinetics for transition metal tellurides in sodium-ion batteries (SIBs). However, the large volume variation and fundamental storage mechanism of these materials remain unsolved. Herein, petal-like N-doped carbon-confined CoTe₂-ZnTe heterostructures (CoZn-Te/NC) are fabricated as anodes in SIBs via a facile bimetal-organic framework-derived strategy. Benefiting from the abundant phase interfaces and dual-defective sites, CoZn-Te/NC composites have fast electrons/ions diffusion and superior pseudocapacitive property. Particularly, introducing a petal-like nitrogen-doped carbon inhibits the particle agglomeration and alleviates volume expansion, thus improving structural stability during cycling. The CoZn-Te/NC exhibits a superior rate capacity of 106 mAh/g at 10 A g⁻¹ and a high reversible capacity of 150 mAh/g at 1.0 A g⁻¹ over 600 long-term cycles. The unique conversion and alloying/de-alloying reaction mechanisms of CoZn-Te/NC are revealed by the in-situ and ex-situ techniques. This work gives promising insights for designing high-performance electrode materials by phase interface, doping, and confining strategy.