Ultrafine Nanocrystals SnS2 Confined on the Inner Wall of Hollow Mesoporous Carbon Nanospheres with Hybrid Storage Mechanism for High-Performance Li+/Na+ Batteries

SnS2 has a large volume change and unstable structure during charging and discharging, seriously hindering its application in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, ultrafine nanocrystals SnS2 are confined to the inner wall of hollow mesoporous carbon nanospheres (HMCNS) by one-step hydrothermal reaction for the first time, forming a special hollow structure with buffer volume effect. After a series of electrochemical analyses, the composite not only displays preeminent long cyclic stability and excellent rate performance, but also shows a hybrid storage mechanism. When used as the anode for LIBs, SnS2@HMCNS maintains a superior capacity of 755 mAh g(-1) after 100 cycles at 0.1 A g(-1) and at 2 A g(-1), the capacity is 547.8 mAh g(-1). Besides, adopted as the anode of SIBs, SnS2@HMCNS exhibits a capacity of 254.5 mAh g(-1) after 1000 cycles at 1 A g(-1), far exceeding that of pure SnS2. The outstanding electrochemical performance is owed to the ultrafine nanocrystals SnS2 adhered to the inner wall of HMCNS, which prevents stacking and increases the active lithium/sodium storage sites. Additionally, the large cavity of HMCNS can provide sufficient buffer space for SnS2 in the process of ion embedding/stripping, optimizing the structural stability of the composite.

Automated summary

In this study, ultrafine nanocrystals SnS2 were successfully confined to the inner wall of hollow mesoporous carbon nanospheres (HMCNS) by one-step hydrothermal reaction, forming a special hollow structure with buffer volume effect. The composite showed outstanding electrochemical performance in lithium-ion batteries and sodium-ion batteries, with excellent cyclic stability and rate performance.