Enhanced Energy Storage Performance of Zr-Doped TiNb2O7 Nanospheres Prepared by the Hydrolytic Method

The use of TiNb2O7 (TNO) as an anode material for Li-ion battery is attracting tremendous attention because of its stable structure and high theoretical capacity. However, the inherent poor electronic conductivity and ionic conductivity restrict its practical application. Herein, we designed and prepared zirconium-doped TiNb2O7 nanospheres (Zrx-TNO NSs, x = 0, 0.05, 0.010) with pores through a simple hydrolysis method to adjust the lattice spacing and electron distribution. The nanosphere-structured electron materials with pores can not only prevent aggregation of active materials but also provide more channels for Li+ and electrons’ transportation. Meanwhile, X-ray diffraction coupled with high-resolution transmission electron microscopy results verified the crystal spacing increasement. The X-ray photoelectron spectrum exhibited partial reduction of metal atoms. As a result, Zr0.05-TNO NSs showed improved cycling stability in the half cell (i.e., delivers a reversible capacity of 170 mA h/g at 5 C after 1000 cycles). It also showed excellent performance in the rate capabilities of 260.0 and 177.8 mA h/g at 0.5 and 10 C, making it highly competitive for quick-charging lithium-ion batteries.