Rutile Ni1/3Nb2/3O2 porous microspheres: A new Li+ -storage anode material

Rutile-structured materials hold great promise as Li[Formula: see text]-storage anode materials, which is based on their energy-storage performance characterized by good safety and unique structures. Nevertheless, currently, the exploration regarding rutile-structured anode materials remains insufficient. In this work, we carry out an exploration on spray-dried Ni[Formula: see text]Nb[Formula: see text]O 2 porous microspheres with a rutile structure, and develop them as a novel Li[Formula: see text]-storage anode material. The precise unit cell parameters derived from the refinement of the measured X-ray diffraction data are presented as follows: [Formula: see text][Formula: see text][Formula: see text][Formula: see text]4.84095(8) Å, [Formula: see text][Formula: see text]2.99592(8) Å, and a unit-cell volume ([Formula: see text]) of 70.209(3) Å 3 . Meanwhile, this novel material features two redox couples, which endows it having a potential to operate safely (approximately 1.19 V) and a practical capacity of 226 mAh g[Formula: see text]. Moreover, it demonstrates excellent performance at high rates, with a capacity of 72 mAh g[Formula: see text] at a current density of 4000 mA g[Formula: see text], and excellent cyclability, with above 115.2% capacity retention over 2500 cycles at 1 A g[Formula: see text]. The electrochemical properties of Ni[Formula: see text]Nb[Formula: see text]O 2 , imply that it can serve as a feasible anode material for applications related to electrochemical energy storage.