Sodium ion storage performance and mechanism in orthorhombic V2O5 single-crystalline nanowires

Abstract

A fundamental understanding of the electrochemical reaction process and mechanism of electrodes is very crucial for developing high-performance electrode materials. In this study, we report the sodium ion storage behavior and mechanism of orthorhombic V 2 O 5 single-crystalline nanowires in the voltage window of 1.0-4.0 V (vs. Na/Na +). The single-crystalline nanowires exhibit a large irreversible capacity loss during the first discharge/charge cycle, and then show excellent cycling stability in the following cycles. At a current density of 100 mA g −1 , the nanowires electrode delivers initial discharge/charge capacity of 217/88 mA h g −1 , corresponding to a Coulombic efficiency of only 40.5%; after 100 cycles, the electrode remains a reversible discharge capacity of 78 mA h g −1 with a fading rate of only 0.09% per cycle compared with the 2 nd cycle discharge capacity. The sodium ion storage mechanism was investigated, illustrating that the large irreversible capacity loss in the first cycle can be attributed to the initially formed single-crystalline α'-Na x V 2 O 5 (0.02 < x < 0.88), in which sodium ions cannot be electrochemically extracted and the α'-Na 0.88 V 2 O 5 can reversibly host and release sodium ions via a single-phase (solid solution) reaction, leading to excellent cycling stability. The Na + diffusion coefficient in α'-Na x V 2 O 5 ranges from 10 −12 to 10 −11.5 cm 2 s −1 as evaluated by galvanostatic intermittent titration technique (GITT).

Magnetic-Stirring-Assisted Hydrothermal Synthesis of Nanosheet-Assembled V6O13 Microflowers with Remarkable Electrochemical Performance for Li-Ion Batteries

“…The binding energies of the V element in TH-VO could be divided into four peaks, which are located at 516.6 and 525.1 eV ascribed to V 5+ , while 516.2 and 523.7 eV ascribed to V 4+ . Analogously, the characteristic peaks of the V element in MSH-VO (V 4+ 2p1/2, V 4+ 2p3/2, V 5+ 2p1/2 and V 5+ 2p3/2) correspond to the binding energies of 522.9, 515.4, 524.1, and 516.7 eV, respectively. − …”

General Carbon Modification Avenue to Construct Highly Stable V2O5 Electrodes for Aqueous Zinc-Ion Batteries

“…After 25 cycles, the R ct value is significantly reduced, and the Warburg impedance ( Z w ) representing the slope is increased in low-frequency region. It improves the penetration process of the electrolyte into the electrode . During the subsequent cycles, the electrode shows a stable R ct value.…”

“…It improves the penetration process of the electrolyte into the electrode. 47 During the subsequent cycles, the electrode shows a stable R ct value. In addition, the Zn/V 2 O 5 @0.25C battery maintains a retention rate of 91.3% after 100 cycles at 1 A g −1 (Figure S5a), revealing its stable structure.…”

Fabrication of Vanadium Oxide@Polypyyrole (V2O5@PPy) Core-Shell Nanofiber Electrode for Supercapacitor

“…36,40 In addition, V2O5@PPy-2 displayed the charge capacitance of 388 F/g at 1 A/g, implying that the intercalation of Na + in V2O5 crystalline. 41 Further, the cycling stability is an important criterion for the practical application of supercapacitor. The specific capacitance retention of electrode materials were investigated at a current density of 3 A/g and shown in Fig.…”