NiFe-MIL-derived Si@C nanoparticles decorated on graphene sheets for efficient lithium storage

Abstract

Recently, silicon-based anode materials have garnered significant attention from researchers due to their high theoretical specific capacity. However, these materials are highly prone to volume expansion, which significantly hinders their further commercialization. Here, the skeleton of silicon nanoparticles (Si NPs) is constructed from metal–organic frameworks (MOFs) in order to buffer their volume increase and enhance electrochemical performance. In this study, a solvent-thermal reaction is conducted using a mixture of NiFe-MIL and sodium hydroxide solution to deposit a carbon layer around the Si NPs, while simultaneously creating a highly conductive graphene network. Si materials supported by inward multi-channel carbon were synthesized through high-temperature pyrolysis. This unique double-layer carbon structure endows the material with remarkable electrochemical properties, including enhanced cycle stability and lithium storage capacity. The Si@C–NiFe-MIL@reduced graphene oxide (Si@C–NiFe-MIL@rGO) electrode materials exhibit a high specific capacity of 2092.8 mA h g⁻¹ at a current density of 50 mA g⁻¹. Furthermore, they demonstrate a stable reversible capacity of 851 mA h g⁻¹ after 200 cycles at a current density of 1000 mA g⁻¹. This research may provide a different strategy for producing high-energy, reasonably priced silicon anodes for lithium-ion batteries (LIBs).