Building Fast Diffusion Channel by Constructing Metal Sulfide/Metal Selenide Heterostructures for High-Performance Sodium Ion Batteries Anode

Heterostructure engineering is one of the most promising modification strategies toward improving sluggish kinetics for the anode of sodium ion batteries (SIBs). Herein, we report a systemic investigation on the different types of heterostructure interfaces' effects of discharging products (Na₂O, Na₂S, Na₂Se) on the rate performance. First-principle calculations reveal that the Na₂S/Na₂Se interface possesses the lowest diffusion energy barrier (0.39 eV) of Na among three kinds of interface structures (Na₂O/Na₂S, Na₂O/Na₂Se, and Na₂S/Na₂Se) due to its smallest recorded interface deformation, similar electronegativity, and lattice constant. The experimental evidence confirms that the metal sulfide/metal selenide (SnS/SnSe₂) hierarchical anode exhibits outstanding rate performance, where the normalized capacity at 10 A g^-1 compared to 0.1 A g^-1 is 45.6%. The proposed design strategy in this work is helpful to design high rate performance anodes for advanced battery systems.