Cobalt–Nickel Vanadate Nanonest Colonies Deposited Carbon Fabric as a Bifunctional Electrode for Li-Ion Batteries and Oxygen-Evolution Reactions

Abstract

Transition metal vanadates (TMVs) have attracted significant attention in various research fields owing to their advantageous features. Furthermore, synthesizing TMVs directly on current collectors at the nanoscale is a promising strategy for achieving better performance. Herein, cobalt–nickel vanadate (CoV₂O₆–Ni₂V₂O₇, CNV) was directly grown on carbon fabric using a facile one-step hydrothermal method. In particular, the CNV sample prepared for 3 h (CNV-3) exhibited a benefit-enriched nanonest-colony morphology in which abundant nanowires (diameter: 10 nm) were intertwined, providing sufficient space for electrolyte diffusion. All the CNV electrodes exhibited good cycling performance in the lithium-ion battery study. Especially, the CNV-3 electrode retained higher discharge and charge capacities of 616 and 610 mAh g⁻¹, respectively at the 100th cycle than the other two electrodes owing to several morphologic features. The electrocatalytic activity of all the CNV samples for the oxygen-evolution reaction (OER) was also explored in an alkaline electrolyte. Among these CNV catalysts, the CNV-3 displayed excellent OER performance and required an overpotential of only 270 mV to drive a current density of 10 mA cm⁻². The Tafel slope of this catalyst was also found to be low (129 mV dec⁻¹). Moreover, the catalyst exhibited excellent durability in a 24 h stability test. These results indicate that the metal vanadates with favorable nanostructures are highly suitable for both energy storage and water-splitting applications.

Graphical Abstract

CoV₂O₆–Ni₂V₂O₇ material grown directly on carbon fabric as novel nanonest colonies demonstrated stable electrochemical response in both lithium-ion battery and oxygen-evolution reaction studies