Synthesis and electrochemical performance of NaV3O8 nanobelts for Li/Na-ion batteries and aqueous zinc-ion batteries

In-situ electrochemical conversion of Na5V12O32@graphene for enhanced cycle stability in aqueous zinc ion batteries

HYPOTHESIS

Na5V12O32 (NVO) is a potential cathode for aqueous zinc ion batteries (AZIBs). However, it suffers severe capacity decay due to the dissolution of the active material. The structural design may be an effective solution to the problem.

EXPERIMENTS

Herein, we construct a typical two-dimensional hierarchical structure of Na5V12O32@graphene (NVO@G) via a facile molten salt method.

FINDINGS

The capacity fading problem is solved by the in-situ conversion of NVO@G to a more stable hierarchical system during cycling. The in-situ formed zinc pyrovanadate (Zn3V2O7(OH)2·2H2O, ZVO) nanosheets on the surface of graphene exhibits excellent zinc-ion storage stability. The presence of graphene induces the growth of NVO nanobelts to construct the typical two-dimensional hierarchical structure. Additionally, the in-situ conversion makes the formed ZVO nanosheets contact with graphene better. Benefitting from the hierarchical nanostructure and in-situ phase conversion, the NVO@G electrode shows excellent long-term stability (96.4% retention after 340 cycles at 0.3 A g-1, 85.7% retention after 4400 cycles at 5 A g-1) and high zinc ion storage capacity (220 mAh g-1 at 0.3 A g-1), which is superior to those of most electrode materials previously reported.

A facile method for pre-insertion of cations and structural water in preparing durable zinc storage vanadate cathodes

For improving the overall energy storage performance of aqueous zinc-ion battery (ZIB) systems, it is important to identify new cathode materials with superior characteristics. Along these lines, in this work,...

Physico-Chemical Properties of NaV3O8 Prepared by Solid-State Reaction

Sodium-vanadium oxide NaV3O8 is synthesized via solid-state method and optimum synthesis conditions are chosen based on the data of DSC and TG analysis. The material synthesized is characterized by X-ray phase analysis, Raman spectroscopy and scanning electron microscopy. The ratio V4+/V5+ in the sample obtained is determined by X-ray photoelectron spectroscopy. Conductivity of the material synthesized was measured by impedance spectroscopy, pulse potentiometry and DC method over the range RT-570 °C. It is shown that NaV3O8 has rather high conductivity essentially electron in type (6.3 × 10-2 at room temperature). AC and DC conductivity measurements are performed and cycling of symmetricNaV3O8|Na3.85Zr1.85Nb0.15Si3O12|NaV3O8 cell in galvanostatic conditions. Thermal stability is studied across 25-570 °C temperature range. The results obtained are compared with the properties of NaV3O8 produced via aqueous solution.

Lithium vanadium oxide (Li1.1V3O8) thick porous electrodes with high rate capacity: utilization and evolution upon extended cycling elucidated via operando energy dispersive X-ray diffraction and continuum simulation

Thick electrode design and charge transport across electrode were probed via operando EDXRD and an expanded continuum model.