Electrochemical Activation in Vanadium Oxide with Rich Oxygen Vacancies for High-Performance Aqueous Zinc-Ion Batteries

Abstract

Environmental concerns promote the development of sustainable energy storage devices. Resource-rich vanadium oxides with easily adjustable valence still exhibit unsatisfactory electrochemical performance stemming from poor electrical conductivity and friable structure as aqueous zinc-ion battery (AZIB) cathodes. Herein, vanadium oxide (VO-300) enriched with oxygen vacancies is acquired via a convenient solvothermal method in combination with subsequent heat treatment, which exhibits a remarkable rate performance of 411.98 mAh•g −1 , and an excellent cycling life for 1500 cycles with 92.8% retention at 10 A•g −1 . The enhanced electrochemical performances of VO-300 can be attributed to more oxygen vacancies, which provide more active sites for zinc-ion storage, expand layer spacing, and increase the conductivity of V 2 O 5 . More pivotal, the activation phenomenon is analyzed, and a two-carrier conversion insertion mechanism of H + domination to Zn 2+ domination is proposed. Based on this mechanism, the V 2 O 5 is transformed into Zn x V 2 O 5 •nH 2 O as an active material for subsequent zinc-ion storage, leading to faster electrochemical kinetics. This work not only demonstrates the potential application of V 2 O 5 as a zinc-ion cathode but also provides new insights into the zinc-ion storage mechanism.

Hydrated Calcium Vanadate Nanoribbons with a Stable Structure and Fast Ion Diffusion as a Cathode for Quasi-Solid-State Zinc-Ion Batteries

“…The key to achieving carbon neutrality is the development of clean, safe, and efficient energy-storage technologies. − Lithium-ion batteries (LIBs) are widely regarded as the most promising energy-storage technology as a result of their exceptional combination of high energy density, long cycle lifespan, absence of memory effect, and low self-discharge. , Although LIBs occupy most of the global energy-storage market, their application in future large-scale energy storage systems is limited by Earth’s limited lithium resources, high preparation costs and flammability, and explosiveness as a result of organic electrolytes. , Accordingly, research is being focused on other new energy-storage technologies that are efficient, safe, and clean. Among them, rechargeable aqueous zinc-ion batteries (AZIBs) offer the advantage of high safety and environmental friendliness as a result of their non-flammable aqueous electrolyte. − Zinc metal has the advantages of high theoretical capacities (820 mAh g –1 and 5854 mAh cm –3 ), low redox potential [−0.76 V versus standard hydrogen electrode (SHE)], high reserves, and low toxicity. , Thus, the emerging ZIBs are receiving extensive research attention. , However, the low specific capacity and instability of the cathode limit the energy density and cycle life of ZIBs. For example, manganese-based materials are structurally unstable during charge/discharge, thereby affecting the battery lifespan. , Prussian blue analogue cathode materials have a low specific capacity despite their high operating voltage. , Among them, vanadium-based materials are receiving extensive research attention for their advantages of open-layer structures and their high theoretical capacity.…”