Carbon nanotubes coupled with layered graphite to support SnTe nanodots as high-rate and ultra-stable lithium-ion battery anodes

Abstract

SnTe exhibits a layered crystal structure, which enables fast Li-ion diffusion and easy storage, and is considered to be a promising candidate for an advanced anode material. However, its applications are hindered by the large volume variation caused by intercalation/deintercalation during the electrochemical reaction processes. Herein, topological insulator SnTe and carbon nanotubes (CNTs) supported on a graphite (G) carbon framework (SnTe-CNT-G) were prepared as a new, active and robust anode material for high-rate lithium-ion batteries by a scalable ball-milling method. Remarkably, the SnTe-CNT-G composite used as a lithium-ion battery anode offered an excellent reversible capacity of 840 mA h g⁻¹ at 200 mA g⁻¹ after 100 cycles and high initial coulombic efficiencies of 76.0%, and achieved a long-term cycling stability of 669 mA h g⁻¹ at 2 A g⁻¹ after 1400 cycles. The superior electrochemical performance of SnTe-CNT-G is attributed to the stable design of its electrode structure and interesting topological transition of SnTe, combined with multistep conversion and alloying processes. Furthermore, in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy were employed to study the reaction mechanism. The results presented here provide new insights to design and reveal the reaction mechanisms of transition metal telluride materials in various energy-storage materials.