Silica Restricting the Sulfur Volatilization of Nickel Sulfide for High-Performance Lithium-Ion Batteries

Nickel sulfides are regarded as promising anode materials for advanced rechargeable lithium-ion batteries due to their high theoretical capacity. However, capacity fade arising from significant volume changes during operation greatly limits their practical applications. Herein, confined NiSx@C yolk-shell microboxes are constructed to address volume changes and confine the active material in the internal void space. Having benefited from the yolk-shell structure design, the prepared NiSx@C yolk-shell microboxes display excellent electrochemical performance in lithium-ion batteries. Particularly, it delivers impressive cycle stability (460 mAh g(-1) after 2000 cycles at 1 A g(-1)) and superior rate performance (225 mAh g(-1) at 20 A g(-1)). Furthermore, the lithium storage mechanism is ascertained with in situ synchrotron high-energy X-ray diffractions and in situ electrochemical impedance spectra. This unique confined yolk-shell structure may open up new strategies to create other advanced electrode materials for high performance electrochemical storage systems.