Tunable and Specific Formation of C@NiCoP Peapods with Enhanced HER Activity and Lithium Storage Performance

The superior properties of nanomaterials with a special structure can provide prospects for highly efficient water splitting and lithium storage. Herein, we fabricated a series of peapodlike C@Ni_2?xCo_xP (x≤1) nanocomposites by an anion‐exchange pathway. The experimental results indicated that the HER activity of C@Ni_2?xCo_xP catalyst is strongly related to the Co/Ni ratio, and the C@NiCoP got the highest HER activity with low onset potential of ～45 mV, small Tafel slope of ～43 mV dec^?1, large exchange current density of 0.21 mA cm^?2, and high long‐term durability (60 h) in 0.5 m H₂SO₄ solutions. Equally importantly, as an anode electrode for lithium batteries, this peapodlike C@NiCoP nanocomposite gives excellent charge–discharge properties (e.g., specific capacity of 670 mAh g^?1 at 0.2 A g^?1 after 350 cycles, and a reversible capacity of 405 mAh g^?1 at a high current rate of 10 A g^?1). The outstanding performance of C@NiCoP in HER and LIBs could be attributed to the synergistic effect of the rational design of peapodlike nanostructures and the introduction of Co element.