Electrochemically alternating voltage induction and in-situ preparation of tin-based multiphase structures anode for sodium-ion batteries

Abstract

Tin-based materials possess a high-capacity as a potential anode for Na-ion batteries (SIBs), but the inferior electric conductivity and sluggish reaction kinetics limit their further development. In this paper, we have successfully constructed multiphase structure SnO2/SnS/SnS2 by combining the electrochemical induction and in-situ hydrothermal method to effectively alleviate these problems. The continuous addition of sulfur source (thioacetamide, TAA) results in the formation of a transition from pure product (SnO2) to double structure (SnO2/SnS), and finally multiphase structure (SnO2/SnS/SnS2). Compared to single or bimetal chalcogenides, the tri-metal chalcogenides have strengthened synergistic effects between diverse components. Additionally, the SnO2/SnS/SnS2 composites exhibit small grain size and abundant mesoporous structure, which aid to shorten the distance of ions transfer and increase surface active sites for Na-ions storage. The SnO2/SnS/SnS2 anode displays optimal diffusion coefficient (1.94 × 10−15 cm2 s−1) and cycling durability, with a recoverable specific discharge ability of 401 mA h g−1 over 100 cycles at 100 mA g−1 and a maintenance overpasses 77 %. These results indicate that the construction of multiphase structures is a prospective way to improve the reaction kinetics of Sn-based materials for SIBs.