Stable Sodium Storage of Red Phosphorus Anode Enabled by a Dual-Protection Strategy.

Red phosphorus is appealing for anode use in sodium-ion batteries. However, the synthesis of electrochemically stable red P anodes remains challenging due to a notable volume variation upon (de)sodiation, and limited synthetic methods arising from the low ignition and sublimation temperatures. To address the above problems, we herein successfully develop an industrially adaptable process for scalable synthesis of affordable phosphorus/carbon (APC) anode materials with an excellent electrochemical performance at a significantly reduced cost. The key to our success is a delicately designed, self-organized, strongly interactive porous P/C structure filled with sodium alginate binder, which maintains the structural integrity of anode and enhances the electrical contact of red P upon its volume variation via a dual protection from porous structure and strong surface interactions. The APC anodes hence present ultrahigh initial Coulombic efficiency (86.2%), excellent cycling stability, and superior rate capability. The industrially adaptable process and excellent electrochemical performance endow the novel APC nano/microspheres with promising applications in high-performance Na-ion batteries.