Abstract
V3O7·H2O nanobelts/reduced graphene oxide (rGO) composites (weight ratio: 86%/14%) are synthesized by a microwave approach with a high yield (85%) through controlling pH with acids. The growth mechanisms of the highly crystalline nanobelts (average diameter: 25 nm; length: ≈20 µm; oriented along the [101] direction) have been thoroughly investigated, with the governing role of the acid upon the morphology and oxidation state of vanadium disclosed. When used as the ZIB cathode, the composite can deliver a high specific capacity of 410.7 and 385.7 mAh g-1 at the current density of 0.5 and 4 A g-1 , respectively, with a high retention of the capacity of 93%. The capacity of the composite is greater than those of V3O7· H2O, V2O5 nanobelts, and V5O12 · 6H2O film. Zinc ion storage in V3O7·H2O/rGO is mainly a pseudocapacitive behavior rather than ion diffusion. The presence of rGO enables outstanding cycling stability of up to 1000 cycles with a capacity retention of 99.6%. Extended cycling shows a gradual phase transition, that is, from the original orthorhombic V3O7· H2 O to a stable hexagonal Zn3(VO4)2(H2O)2.93 phase, which is a new electrochemical route found in V3O7 materials. This phase transition process provides new insight into the reactions of aqueous ZIBs.
Original language | English |
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Article number | e2100558 |
Journal | Small |
Volume | 17 |
Issue number | 24 |
Number of pages | 10 |
ISSN | 1613-6810 |
DOIs | |
Publication status | Published - 2021 |
Keywords
- Microwave-assisted synthesis
- Phase transition
- Reduced graphene oxide
- V3O7H2O nanobelts
- Zinc-ion batteries