Amorphous Red Phosphorus Embedded in Highly Ordered Mesoporous Carbon with Superior Lithium and Sodium Storage Capacity

Red phosphorus (P) have been considered as one of the most promising anode material for both lithium-ion batteries (LIBs) and (NIBs), because of its high theoretical capacity. However, natural insulating property and the large volume expansion of red P during cycling lead to poor cyclability and low rate performance, which prevents its practical application. Here, we significantly improves both lithium storage and sodium storage performance of red P by confining nanosized amorphous red P into the mesoporous carbon matrix (P@CMK-3) using a vaporization-condensation-conversion process. The P@CMK-3 shows a high reversible specific capacity of ∼2250 mA h g^-1 based on the mass of red P at 0.25 C (∼971 mA h g^-1 based on the composite), excellent rate performance of 1598 and 624 mA h g^-1 based on the mass of red P at 6.1 and 12 C, respectively (562 and 228 mA h g^-1 based on the mass of the composite at 6.1 and 12 C, respectively) and significantly enhanced cycle life of 1150 mA h g^-1 based on the mass of red P at 5 C (500 mA h g^-1 based on the mass of the composite) after 1000 cycles for LIBs. For Na ions, it also displays a reversible capacity of 1020 mA h g^-1 based on the mass of red P (370 mA h g^-1 based on the mass of the composite) after 210 cycles at 5C. The significantly improved electrochemical performance could be attributed to the unique structure that combines a variety of advantages: easy access of electrolyte to the open channel structure, short transport path of ions through carbon toward the red P, and high ionic and electronic conductivity.