Copyright © 2022 Foshan MBRT Nanofiberlabs Technology Co., Ltd All rights reserved.Site Map
Today, lithium-ion batteries (LIBs) are widely used in electric vehicles and portable electronic devices due to their high energy density and impressive cycle stability. However, limited lithium resources and safety concerns have significantly hindered the future development of LIBs. Recently, alternative devices such as sodium-ion batteries (SIBs), potassium-ion batteries (KIBs), and zinc-ion batteries (ZIBs) have emerged as ideal candidates for next-generation energy storage systems. In particular, aqueous zinc ion batteries (ZIBs) have shown greater potential due to the significant advantages of zinc metal, such as low redox potential (-0.76 V compared to standard hydrogen electrodes), ultra-high theoretical capacity (820 mA h g-1), abundant resources, high safety, and low cost. Recent research advances have focused on the development of high-performance cathodes for efficient ZIB, and a variety of materials such as manganese compounds, Prussian blue analogs, organic polymers, and vanadium-based oxides have been developed. Among these materials, vanadium oxides including V2O5, VO2, and V2O3 are promising because of their high reversible capacity and outstanding rate performance due to their various crystal structures and valence states. However, the practical application of vanadium oxide cathodes is still severely limited by their inherent drawbacks, such as sluggish Zn2+/electron transfer kinetics due to low conductivity and poor stability due to severe structural degradation during cycling.
The main point of this paper
Strategies to enhance the electrochemical properties of vanadium oxide:
Design of nanoscale materials.
Incorporate metal ions.
Construction of composite materials.
Fabrication of layered vanadium oxide cathodes due to their two-dimensional structure providing active sites and increased contact area.
Combining nanocarbon with vanadium oxides:
Combining nanocarbon (e.g. graphene, carbon nanotubes and porous carbon) promotes Zn2+/electron transport and maintains structural stability.
Nanocarbon has excellent electrical conductivity and chemical stability.
Industrial Application Challenges:
The preparation of efficient layered/nanocarbon vanadium oxide composite cathodes is challenged by low-cost and simple methods.
Conventional synthesis methods are energy intensive, have many steps, long production times and generate contaminants.
Flash Joule Heating (FJH) Technology:
Provides ultra-high temperatures and ultra-fast heating/quenching rates.
Simplifies heating steps, reduces energy consumption and makes material synthesis easier, more economical and more efficient.
Application examples of FJH technology:
Rapid synthesis of graphene and transition metal layered hydroxides.
Innovative point of this study:
Rapid fabrication of VO2/V2O5 microstructures and graphene-like carbon nanosheet (VOG) composites by treating commercial V2O5 powders with the FJH procedure.
Instantaneous high-temperature heating and quenching by FJH transformed the V2O5 powder into layer-stacked VO2/V2O5 microstructures and etched the graphite paper substrate surface to introduce graphene-like carbon nanosheets.
Performance Overview:
VOG composites exhibit excellent electrochemical properties when used as cathode materials in aqueous zinc ion batteries (ZIB). The specific capacity was up to 459 mA h g-1 at 0.2 A g-1
After 2500 cycles at 1.0 A g-1, the capacity retention was 355.5 mA h g-1
After 10,000 cycles at 10 A g-1, the capacity was maintained at 169.5 mA h g-1
Preparation method:
The VOG composites were prepared by flash joule heating (FJH) technique in only 2.5 seconds
This method handles commercial V2O5 powder, which is melted, aggregated and reduced into layered VO2/V2O5 microstructures by rapidly generating high temperatures, while graphene-like carbon nanosheets are exfoliated from the graphite paper substrate to form a composite structure
Performance Advantages:
The superior performance is attributed to the abundance of active sites and built-in electric fields in the layered VO2/V2O5 heterostructures, as well as the excellent electrical conductivity of graphene-like carbon nanosheets, which accelerate charge transfer and mitigate structural degradation
In conclusion, we demonstrate a facile and ultrafast synthesis of composites consisting of layer-stacked VO2/V2O5 microstructures and graphene-like carbon nanosheets by the FJH technique. As a cathode for aqueous ZIBs, the prepared composite achieves an admirable stability of 355.5 mA h g-1 after 2500 cycles at 1.0 A g-1 and 169.5 mA h g-1 after 10,000 cycles at 10 A g-1. Further electrochemical measurements show that such excellent performance is due to the richness of the layered stacked VO2/V2O5 heterostructures and graphene-like carbon nanosheets. V2O5 heterostructure has abundant sites and built-in electric fields, which accelerates the electron/Zn2+ transfer and mitigates the structural degradation, as well as the excellent electrical conductivity of graphene-like carbon nanosheets. This work provides a novel and effective approach to obtain high-performance vanadium oxide-based cathodes for efficient ZIB.
