phd-2021

Vanadium-based Nanomaterials for Energy Storage Applications

The demand for lithium-ion batteries (LIBs) are growing rapidly, driven by the market of personal electronics and electric vehicles. However, the price and safety issue of the LIBs limit the large-scale applications for storing intermittent renewable electricity. Thus, the search for suitable electrode material for LIBs and alternative low-cost aqueous multi-ion battery are always ongoing studies. Vanadium-based materials with various oxidation states and rich crystal structures have been regarded as the promising electrode materials for the next-generation batteries. Herein, the first work is aiming to design anode materials for LIBs with a highly stable electrochemical performance. It has been demonstrated that the carbon coated zinc vanadate anode exhibits a high stable specific capacity. Meanwhile, the interesting changes of the vanadium oxidation state during calcination process are systematically investigated, as well as a metal ion ratio changes. It will not only help us to estimate the number of electrons that can be transferred, but also to identify the chemical reactions during the charge and discharge process. Aqueous zinc-ion batteries (ZIBs) are eco-friendly and safe, possessing a high theoretical capacity. The existing major challenge is the rather poor long-life storage capability, since the hydrated zinc ion is of a considerable size (0.43 nm). Thus, the second work is to find an appropriate cathode electrode material. Presently, the fundamental understanding of battery reactions in ZIB electrode materials upon long-term operation remains superficial. In this project, I combine vanadium oxide nanobelt with reduced graphene oxides into ZIB cathode materials, which can operate efficiently for 1000 cycles. Moreover, such an excellent stability allows the discovery of a new phase transition of vanadium oxides from orthorhombic to hexagonal structure

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Supervisors

Assoc. Prof. Susanne Mossin

 

Co-supervisor

Prof. Poul Norby