Controllable 3D Porous Ni Current Collector Coupled with Surface Phosphorization Enhances Na Storage of Ni 3 S 2 Nanosheet Arrays.

3D porous Ni is fabricated via an easily scalable electroless plating method using a dynamic template formed through in-situ hydrogen bubbles. The pore size in the range of several micrometers is controllable through adjusting the Ni ²⁺ depositing rate and hydrogen bubbles releasing rate. The Ni ₃ S ₂ nanosheet arrays anode is then grown on the unique 3D porous Ni current collector followed by subsequent surface phosphorization. The tremendous interconnected pores and rich voids between the Ni ₃ S ₂ nanosheet arrays cannot only provide rapid transferring channels for Na ⁺ , but also accommodate volumetric changes of the Ni ₃ S ₂ electrode during cycling, guaranteeing the integrity of the active material. In addition, the surface phosphorized layer enhances the electronic conductivity through providing an electron transport highway along the 3D Ni ₃ S ₂ , NiP ₂ layer, and 3D porous Ni current collector, and simultaneously stabilizes the electrode/electrolyte interphase as a protecting layer. Because of these merits, the phosphorized 3D porous Ni ₃ S ₂ (3D P-Ni ₃ S ₂ ) electrode is capable of delivering an ultra-stable capacity of 387.5 mAh g ^-1 at 0.1 A g ^-1 , and a high capacity retention of 85.3% even at a high current density of 1.6 A g ^-1 .
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