Core-Shell CoSn@CoSnO x Nanoparticles Encapsulated in Hollow Carbon Nanocubes as Anodes for Lithium-Ion Batteries

Sn-based materials are considered as a promising candidate for anodes of lithium-ion batteries (LIBs). However, rapid capacity fading associated with large volume expansion during cycling impedes the commercialization of Sn-based anodes. Herein, a yolk-shell structure is designed via a thermal reduction method and following in situ surface oxidation. In this configuration, CoSn nanoparticles covered by a conformal surface oxide layer are encapsulated in hollow carbon nanocubes. When utilized as an anode material for LIBs, the CoSn@CoSnO x @C exhibits a high discharge capacity of 1177 mAh g(-1) after 180 cycles at 0.2 A g(-1) and a capacity retention of 86.7% after 500 cycles at a higher current density of 1 A g(-1). The investigation demonstrates that the outstanding electrochemical performance of the composite anodes can be attributed to the synergistic effects of the yolk-shell structure, nanosized CoSn alloy core, and conformal surface oxide layer. This elaborately designed structure can be extended to other alloy-type anode materials to tackle the capacity decay induced by volume expansion.

Automated summary

The yolk-shell structure designed through thermal reduction and in situ surface oxidation shows high discharge capacity and good cycling stability for CoSn@CoSnO x @C as a lithium-ion battery anode material.