Transition metal modification of graphene oxide membranes for enhanced aqueous stability and dielectric performance

Abstract

Graphene oxide (GO) membranes, known for their high dielectric constant and low dielectric loss, have emerged as promising separators for advanced energy storage and transfer devices. While previous research has focused on the aqueous stability enhancement by high-valence metal cations, their effect on modifying the dielectric properties of GO membranes remains understudied. This study investigates the impact of transition metal cation modification on the aqueous stability and dielectric properties of graphene oxide (GO) membranes. Multivalent transition metal chlorides (FeCl₃, FeCl₂, CuCl₂, and CuCl) were introduced during the self-assembly process to create modified GO membranes. The membranes were characterized using various techniques, including zeta potential measurements, contact angle measurements, FTIR spectroscopy, and XRD spectroscopy. The aqueous stability of the modified membranes was evaluated, and their dielectric performance was assessed using capacitance measurements across a frequency range of 0.1 Hz to 10⁵ Hz. The results demonstrate that the choice of transition metal cation and its oxidation state significantly influence the morphology, aqueous stability, and dielectric properties of the GO membranes. Notably, Fe³⁺ and Cu²⁺ modifications enhanced aqueous stability, while Fe²⁺ and Cu⁺ modifications improved dielectric performance. This study provides insights into tailoring the properties of GO membranes for various applications, including energy storage and transfer devices.