Core-shell SnSe@TiO2/C heterostructure high-performance anode for Na-ion batteries

Highlights: : • A core-shell SnSe@TiO₂/C composite has been synthesized by the arc-discharge method. • TiO₂ acts as a protective shell on SnSe. • Excellent capacity and rate performance are achieved. -- Abstract: The core-shell SnSe@TiO₂/C heterostructure composite with high reactivity, small size, and superior electrochemical performance for sodium-ion batteries (SIBs) was synthesized for the first time using a controllable arc-discharge technique. The electrochemical measurements demonstrate that the outstanding mechanical stability of the TiO₂ shell can improve the cycling stability, rate capability, and high specific capacity of SnSe. The as-prepared core-shell SnSe@TiO₂/C composite combines the benefits of SnSe and TiO₂, with SnSe nanoparticles improving ion diffusion kinetics and specific capacity while TiO₂ maintains excellent cycling stability. Furthermore, the core-shell heterostructure approach can synergistically reduce volume fluctuation and aggregation of active materials during cycling. At a current density of 1 A/g, the capacity can reach 318 mAh/g, with a steady cycling performance of 1100 cycles. The novel core-shell heterostructure composite is expected to be a promising candidate as an anode material for next-generation high-performance SIBs due to its outstanding electrochemical performance and ease of synthesis for large-scale production.