Sodium Storage Behavior of Nanoporous Sb/MCNT Anode Material with High Cycle Stability by Dealloying Route

To improve the cycle performance of Sb-based anode materials for sodium storage, a simple two-step method (mechanical assisted chemical alloying and acid dissolution dealloying) is proposed to prepare nano sized and porous antimony/multi-walled carbon nanotube (De-Sb/MCNT) composite. Different methods were employed to characterize the physicochemical and electrochemical properties of De-Sb/MCNT material as anode for sodium storage. The results show that compared to the Raw-Sb/MCNT obtained by direct ball milling of commercial raw Sb and MCNT, the De-Sb/MCNT material exhibits better cycle performance of sodium storage. At a current density of 200 mA.g(-1), the De-Sb/MCNT delivers the reversible specific capacity of 408.6 mAh.g(-1) with the initial Coulombic efficiency of 69.2%. After 330 cycles at 800 mA.g(-1), the capacity retention rate can still retain 88%. The superior cycle performance of De-Sb/MCNT benefits from the "pre-pulverization" effect of mechanically-assisted chemical alloying/acid dissolution dealloying on commercial Sb, which promotes the nanocrystallization and porosity of the material. The De-Sb/MCNT relieves the volume expansion during charging and discharging, thus achieving excellent cycle stability. This dealloying process at ambient temperature is expected to provide a new approach for sodium storage of alloy anode materials with prolonged and stable cycles.