Simply mixed commercial red phosphorus and carbon nanotube composite with exceptionally reversible sodium-ion storage.

Recently, sodium ion batteries (SIBs) have been given intense attention because they are the most promising alternative to lithium ion batteries for application in renewable power stations and smart grid, owing to their low cost, their abundant natural resources, and the similar chemistry of sodium and lithium. Elemental phosphorus (P) is the most promising anode materials for SIBs with the highest theoretical capacity of 2596 mA h g(-1), but the commercially available red phosphorus cannot react with Na reversibly. Here, we report that simply hand-grinding commercial microsized red phosphorus and carbon nanotubes (CNTs) can deliver a reversible capacity of 1675 mA h g(-1) for sodium ion batteries (SIBs), with capacity retention of 76.6% over 10 cycles. Our results suggest that the simply mixed commercial red phosphorus and CNTs would be a promising anode candidate for SIBs with a high capacity and low cost.