A low-cost NiSe2 derived from waste nickel foam as a high-performance anode for sodium ion batteries

Nickel selenide has a splendid future to become a hot anode for sodium ion batteries owing to the high theoretical capacity and unique electrical conductivity. Nevertheless, exploring low cost and high-performance nickel selenide is still critical to further application. Herein, NiSe2 with micro-structured features has been synthesized through a low-cost and one-step selenidation approach using disused nickel foam as raw material. Eminent reversible capacity (515 mAh g−1 at 0.1 A g−1), superior rate capability (310 mAh g−1 at 10 A g−1), and excellent cycling stability (318 mAh g−1 after 800 cycles at 1 A g−1) are exhibited for NiSe2 prepared at 550 °C for 4 h. Importantly, the initial Coulombic efficiency is also impressive (96%). Furthermore, the electrochemical mechanism is sufficiently explored by means of ex situ X-ray diffraction (XRD) and transmission electron microscopy (TEM). Besides, employing Na3V2(PO4)2F3@rGO as cathode and NiSe2 as anode has been assembled the sodium ion full battery, which delivers two high discharge plateaus of 1.86 and 2.72 V and reveals preeminent rate capacity and cycling stability. This work will come out with a new avenue for fostering the evolution of new metal selenide materials for energy storage and others.