Solvothermal synthesis of sea urchin-like NaxV2O5 structure for ultra-high stability aqueous zinc ion batteries

Abstract

Vanadium pentoxide, as a low-cost, safe and reliable cathode electrode material. Its structure is prone to collapse during the process of repeated Zn²⁺ intercalation and deintercalation of aqueous zinc-ion batteries (AZIBs), so enhancing the structural stability of vanadium pentoxide and improving the rate performance has always been a challenge. In this work, sea urchin-like Na_xV₂O₅ vanadate materials are obtained by solvothermal reaction, and the prepared samples exhibit a fast ion transport path during the process of Na⁺ chemical embedding in V₂O₅ framework, which is due to the plentiful active sites that nanowires can provide. This paves the way for high magnification performance. In addition, the unique sea urchin-like morphology with a large specific surface can continuously adapt to strain during ion insertion to obtain excellent long cycle performance. The above merits endow NaVO with a highly stable discharge capacity of 250.5 mA g⁻¹ at 0.5 A/g and a long cycle capacity of 100 mA h g⁻¹ maintains for more than 11,000 cycles at 10 A/g. Remarkably, the capacity retention rate up to 85.7%.