Spindle Single-Crystalline Rutile TiO₂ with Excellent Cyclability for Low-Cost Li-Storage Materials

Abstract

We investigated the Li storage properties of spindle single-crystalline rutile TiO 2 fine particles synthesized by a large-scale sulfate process. Their anode properties were compared with those of polycrystalline rutile TiO 2 particles. An increase in the degree of single-crystal formation improved the charge−discharge capacity and initial Coulombic efficiency. In situ X-ray diffraction and transmission electron microscopic observation demonstrated the structural integrity of the spindle particles during the charge−discharge reactions. These results concluded that the degree is a critical parameter determining the anode performance of rutile TiO 2 . The anode performance was further enhanced by doping Nb into the spindle TiO 2 particles. These findings suggest that singlecrystalline rutile TiO 2 particles are very promising low-cost and high-performance Li storage materials.

Effects of Phase Change and Cu Doping on the Li Storage Properties of Rutile TiO₂

“…24 A large slope in the low potential region obtained during the first lithiation process is a typical feature of rutile TiO2 electrodes. [10][11][12][13][14][15][16][18][19][20] The initial discharge capacity was 257 mAh g −1 , and the charge-discharge curves of the second and third cycles were fully consistent with each other, indicating high reversibility of the electrode reactions. The electrode capacity was maintained at 220 mAh g −1 until the 10th cycle (Fig.…”

“…16 The authors of this work focused on the impurity doping and high crystallization degree of rutile TiO2. [18][19][20] We performed Nb doping of rutile TiO2 18 and demonstrated that a Nb-doped TiO2 electrode exhibited a very high rate capability of 120 mAh g -1 even at a high rate of 50C. 19 In addition, we achieved an outstanding cyclability with 170 mAh g -1 during 5500 cycles at 1C by using single-crystalline rutile TiO2.…”

“…19 In addition, we achieved an outstanding cyclability with 170 mAh g -1 during 5500 cycles at 1C by using single-crystalline rutile TiO2. 20 After reporting the remarkable rutile doping effect, the number of research studies on impurity-doped rutile TiO2 significantly increased. 21,22 An irreversible phase change of rutile TiO2 during the initial lithiation process has been recently observed by in-situ X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM).…”

“…The main effects of doping rutile TiO2 electrodes are the increase in electronic conductivity and the expansion of a Li+ diffusion pathway, which has been reported by the authors. [18][19][20] Thus, it is interesting to know how doping affects the TiO2 electrode after the phase change. In this study, we investigated the crystal structure of TiO2 after the phase change and the influence of impurity doping on TiO2 anode properties.…”

Crystalline-Amorphous Hybrid CoNiO2 Nanowires with Enhanced Capacity and Energy Density for Aqueous Zinc-Ion Hybrid Supercapacitors

“…Li + , Na + , K + , Zn 2+ , and other metal ion hybrid energy storage systems have emerged and attracted widespread interest with the rapid development of renewable energy. − Compared with the limitations of Li + and Na + as well as K + nonaqueous energy storage systems, it is noted that aqueous zinc-ion batteries (ZIBs) and zinc-ion hybrid supercapacitors (ZHSs) have particularly attracted numerous attention because of their high capacity, low redox potential, safety, and environmental friendliness. − Among these systems, ZHSs are constructed with a battery-type anode (Zn electrode) and capacitive cathode materials. , Therefore, they combine the energy storage mechanism of supercapacitors and batteries into one system and possess merits of high energy and power densities, giving broad application prospects in mobile communications and electronic equipment. , Despite all the advantages and research interest in ZHSs, the excellent performance of ZHSs largely depends on seeking for cathode materials with high capacity and stable structures.…”