Unraveling the atomic-level manipulation mechanism of tin-based ternary anodes via hetero-anion engineering for stable sodium ion storage

The gradual retardation of heterogeneous interface reactions during extended cycling results in significant capacity loss, particularly in the initial few cycles. This is due to the inhomogeneous distribution and structural degradation of heterointerfaces. Currently, a range of atomic-level tuning strategies are employed to enhance the intrinsic transfer characteristics for sodium-ion batteries (SIBs). Herein, the defect-rich single-phase ternary tin sulfide selenide (SnSe1.33S0.67) anode is constructed via favorable heteroatom(S) introducing. Such a defective open structure employed as anodes for SIBs, delivers a superior rate performance of 452.3 mAh g−1 at 5.0 A g−1, and excellent cycling stability, with a capacity retention of 535.8 mAh g−1 after 500 cycles at 1.0 A g−1. The exceptional performance is attributed to the rapid diffusion of ions/electrons through lattice defects and heteroatom coexistence, as well as the high tolerance for volume changes resulting from optimized phase transition modes and enhanced structural rigidity, as demonstrated by experimental results and density functional theory (DFT) calculations. Through the heteroatoms injection strategy, this work offers deeper insights into the correlation between precise regulation of internal defects and superior storage performance in SIBs.