Nitrogen-Doped Carbon-Confined Ni_0.6Fe_0.4Se₂ Nanoboxes Bridged by Carbon Nanotube Networks for Efficient Sodium-Ion Batteries

Abstract

The reasonable design of effective anode materials while simultaneously achieving rapid rate capacity and satisfied long lifespan is urgently required yet still challenging for sodiumion batteries (SIBs). Herein, we design and build Ni 0.6 Fe 0.4 Se 2 nanoboxes confined by a nitrogen-doped carbon layer and bridged by carbon nanotube networks (Ni 0.6 Fe 0.4 Se 2 @NC/CNTs) via a precipitation method combined with a carbonization and selenylation process to suitable anode materials toward efficient SIBs. The obtained Ni 0.6 Fe 0.4 Se 2 @NC/CNTs combines multiple merits of ample ion/electron active sites of hierarchical structure, enhanced ability to mitigate substantial volume expansion of nitrogen-doped carbon sheet layers, and fast electron-and Na +transfer kinetics induced by high conductivity of the interconnected carbon nanotube networks. As expected, the optimized Ni 0.6 Fe 0.4 Se 2 @NC/CNTs render a prominent sodium storage performance with an exceptional reversible capacity (564.3 mAh g −1 after 100 cycles at 0.1 A g −1 ) and a superior prolonged cycle lifespan (401.1 mAh g −1 at 5.0 A g −1 over 1000 long-term cycles), surpassing most previously reported NiFe-based electrodes to our knowledge. This work hereby highlights a practical strategy for engineering advanced anode materials for high-efficiency SIBs.