Novel Fe2P/graphitized carbon yolk/shell octahedra for high-efficiency hydrogen production and lithium storage

Abstract

We successfully designed and synthesized thin octahedral graphitized carbon shells with Fe₂P particles enveloped inside them through a simple hydrothermal method and calcination process. Notably, the precursor Fe₂PO₅/polymeric layer octahedra (FPO/PLO) composite was one-step synthesized via a hydrothermal route. The final Fe₂P/graphitized carbon (Fe₂P/GC) yolk/shell octahedra composite was used for both the hydrogen evolution reaction (HER) and lithium-ion batteries (LIBs). In 0.5 M H₂SO₄ aqueous solution, the obtained Fe₂P/GC yolk/shell octahedra composite possessed a strong catalytic activity towards the HER. The overpotential requirement to obtain a 10 mA cm⁻² current density was as low as 76 mV. The as-prepared composite was also applied in LIBs as the anode electrode. The electrochemical test exhibited a steady specific capacity of ∼627 mA h g⁻¹ and a nearly 100% coulombic efficiency at a current density of 0.1 A g⁻¹. Therefore, the Fe₂P/GC yolk/shell composite is a promising anode for use in LIBs and presents a high specific capacity, favorable rate capability, and a long circulatory stability.