Red Phosphorus Single-Walled Carbon Nanotube Composite as a Superior Anode for Sodium Ion Batteries

Sodium ion batteries (SIBs) have been,considered as a top alternative to lithium ion batteries due to the earth abundance and low cost of sodium compared With lithium. Among all proposed anode materials for SIBs, red phosphorus (P) is a very promising candidate because it:has the highest theoretical capacity (similar to 2600 mAh/g). In this study, a red P-single-walled carbon nanotube (denoted as red P-SWCNT) composite, in which red P is uniformly distributed between tangled SWCNTs bundles, is fabricated by a modified vaporization-condensation method. Benefiting from the nondestructive preparation process, the highly conductive and mechanically strong SWCNT network is preserved, which enhances the conductivity of the composite and stabilizes the solid electrolyte interphase. As a result, the red P-SWCNT composite presents a-high overall sodium storage capacity (similar to 700 mAh/g(composite) at 50 mA/g(composite)), fast rate capability (similar to 300 mAh/g(composite) at 2000 mA/g(composite)), and stable long-term cycling performance with 80% capacity retention after 2000 sodiation-desodiation cycles. The red P-SWCNT composite fabricated by the vaporization condensation method significantly extends the cycling stability of P/carbon composite from current similar to 100 cycles to similar to 2000 cycles.