Layered sodium vanadate (NaV8O20) nanobelts: a new high-performing pseudocapacitive material for sodium-ion storage applications†

Multifunctional layered nanostructures have attracted great attention for next-generation electrochemical supercapacitors and metal-ion batteries. Herein, we use a hydrothermal method to demonstrate the synthesis of 1D and layered sodium vanadate (NaV₈O₂₀) nanobelts architecture. These NaV₈O₂₀ nanobelts demonstrate outstanding electrochemical performance in supercapacitors (SCs) and sodium-ion batteries (SIBs). The possible formation mechanism of NaV₈O₂₀ nanobelts is briefly discussed. Benefiting from the 1D and layered nanostructure, pre-inserted cations, significantly enhanced electrochemical conductivity, and high electroactive surface area, the prepared NaV₈O₂₀ electrode material exhibited excellent charge storage capacity, favorable rate, and cyclic stability performance. The NaV₈O₂₀ nanobelts displayed outstanding electrochemical characteristics, including 676 F g⁻¹ of specific capacitance, 45 W h kg⁻¹ of energy density and 5224 W kg⁻¹ of power density. Additionally, on testing in Na-ion batteries, the NaV₈O₂₀ nanobelts exhibit a discharge capacity of 110 mA h g⁻¹ at 10 mA g⁻¹ and retain ∼52% capacity after 100 cycles. Along with this, the galvanostatic intermittent titration technique (GITT) measurements reveal a high diffusion coefficient for Na⁺ ions, highlighting the efficient Na⁺ ions transportation within the NaV₈O₂₀ structure. To our knowledge, this is the first report on the use of NaV₈O₂₀ nanobelts for both SIBs and SCs, marking a significant contribution to the development of multifunctional materials for energy storage applications.