High-capacity and ultrastable lithium storage in SnSe₂-SnO₂@NC microbelts enabled by heterostructures

The ingenious design of high-performance tin-based lithium-ion batteries (LIBs) is challenging due to their poor conductivity and drastic volume change during continuous lithiation/delithiation cycles. Herein, we present a strategy to confine heterostructured SnSe₂-SnO₂ nanoparticles into macroscopic nitrogen-doped carbon microbelts (SnSe₂-SnO₂@NC) as anode materials for LIBs. The composites exhibit an excellent specific capacity of 436.3 mA h g^-1 even at 20 A g^-1 and an ultrastable specific capacity of 632.7 mA h g^-1 after 2800 cycles at 5 A g^-1. Density Functional Theory (DFT) calculations reveal that metallic SnSe₂-SnO₂ heterostructures endow the lithium atoms at the interface with high adsorption energy, which promotes the anchoring of Li atoms, and enhances the electrical conductivity of the anode materials. This demonstrates the superior Li⁺ storage performance of the SnSe₂-SnO₂@NC microbelts as anode materials.