Dual-MOF-derived FeNi@NC as an advanced anode for sodium-ion batteries with ultra-long cycle life

Developing high-performance and cost-effective anode materials is essential for advancing sodium-ion battery (SIB) technology. In this study, a dual–metal–organic framework (dual-MOF) strategy was employed to synthesize the Fe 2 Ni MIL MOF@ZIF-8 precursor. After high-temperature carbonization, this precursor was transformed into a composite comprising FeNi alloy nanoparticles encapsulated within N-doped carbon nanotubes (FeNi@NC). Benefiting from its unique three-dimensional porous architecture, the N-doped carbon nanotubes shorten Na + diffusion pathways and accelerate electron transport, while the FeNi alloy nanoparticles supply abundant electrochemical active sites and enhance electrical conductivity. Moreover, the carbon matrix effectively alleviates volume expansion by providing structural confinement. Consequently, when used as an anode for SIBs, it delivers an outstanding long-term cycling life (290.39 mAh g −1 after 1000 cycles at 0.5 A g −1 ) and a high capacity (385.68 mAh g −1 after 200 cycles at 0.1 A g −1 ). The present strategy holds great promise for deriving porous carbon-based materials from MOFs for next-generation energy-storage applications.