Novel peapod-like Ni₂P nanoparticles with improved electrochemical properties for hydrogen evolution and lithium storage

A novel peapod-like Ni₂P/C nanocomposite is designed and synthesized using NiNH₄PO₄H₂O nanorods as templates. With enriched nanoporosity and large active surface areas, the peapod-like composites offer superb dual functionality as both electrocatalysts for the hydrogen evolution reaction (HER) and anodes for lithium ion batteries (LIBs). Electrochemical tests demonstrate that the Ni₂P/C nanocomposite exhibits an overpotential as low as 60 mV and a notably low Tafel slope of 54 mV dec.^-1. When used as an anode material for lithium-ion batteries, the resulting peapod-like Ni₂P/C nanocomposite delivers high specific capacitances of 632 mA h g^-1 at 0.1 A g^-1 and 439 mA h g^-1 at 3 A g^-1, and also exhibits a superior cycling performance, with nearly 100% capacity retention even after 200 charge-discharge cycles at a charge-discharge rate of 0.1 A g^-1. The work demonstrates that the peapod-like materials reported herein are promising materials for electrochemical energy-related applications such as HER and LIBs.