Sodium-ion batteries (SIBs), a potential alternative to lithium ion batteries (LIBs), have attracted remarkable attention recently due to the natural abundance and low-cost of sodium. Here, we have presented a comprehensive study on combining electroless deposition with chemical dealloying to control the shell thickness and composition of a red phosphorus (RP)@Ni–P core@shell nanostructure as a high performance anode for SIBs. For the first time depending on regulating the dealloying time (1 h, 4 h, 8 h, 10 h and 20 h) of RP@Ni–P synthesized by electroless deposition of Ni on RP, 1 h RP@Ni–P, 4 h RP@Ni–P, 8 h RP@Ni–P, 10 h RP@Ni–P and 20 h RP@Ni–P with different shell thicknesses and compositions were prepared. The in situ generated Ni₂P on RP particle surfaces can facilitate intimate contact between RP and a mechanically strong amorphous Ni–P outer shell with a high electronic conductivity, which ensures strong electrode structural integrity, a stable solid electrolyte interphase and ultra-fast electronic transport. As a result, the 8 h RP@Ni–P composite presents a super high capacity (1256.2 mA h g_composite ⁻¹ after 200 cycles at 260 mA g_composite ⁻¹), superior rate capability (491 mA h g_composite ⁻¹ at 5200 mA g_composite ⁻¹) and unprecedented ultralong cycle-life at 5000 mA g_composite ⁻¹ for an RP-based SIB anode (409.1 mA h g_composite ⁻¹ after 2000 cycles). This simple scalable synthesis approach will provide a new strategy for the optimization of core@shell nanostructures, paving the way for mass production of high performance electrodes for SIBs and other energy storage systems.

As a potential alternative to lithium-ion batteries (LIBs), sodium-ion batteries (SIBs) have received more and more attention due to the low cost of sodium and similar chemical properties of sodium and lithium. Developing high performance anode materials is one of the major challenges for SIBs. Red phosphorus (RP) is considered as one of the most promising anodes for SIBs with a high theoretical specific capacity of about 2600 mA h g⁻¹, tackling serious challenges, such as large volume change and low electrical conductivity during the charge–discharge process. Herein, we have demonstrated a novel hollow nanoporous red phosphorus (HNPRP) with a small amount of iodine doping as an advanced anode for SIBs via combining a typical redox reaction and boiling process. The HNPRP exhibits a high capacity of 1658.2 mA h g⁻¹ after 100 cycles at 0.26 A g⁻¹, superior rate capability (759.6 mA h g⁻¹ at 5.2 A g⁻¹) and ultralong cycle-life (857.3 mA h g⁻¹ after 1000 cycles at 2.6 A g⁻¹) as an anode for sodium-ion batteries (SIBs). The excellent electrochemical performance is due to its innovative electrode design, which ensures high sodium ion accessibility, strong structural integrity and fast electrode transport. The scalable strategy shall pave the way for the preparation of high performance electrodes for SIBs and other energy storage systems, providing new guidelines for the synthesis of hollow nanoporous structures.

A facile method is reported to stabilize Li-metal anodes via constructing a solid–solution-based Li–Mg alloy.