Graphene oxide: An effective ionic conductivity promoter for phosphoric acid-doped poly (vinyl alcohol) gel electrolytes

Recently, incorporation of nanomaterials into gel electrolytes has been used to improve the electrochemical performance of energy storage devices. Here, graphene oxide-based gel electrolyte samples were prepared by exploiting Poly (vinyl alcohol) as the polymer matrix and H₃PO₄ as ion producer. There has been a significant improvement in ionic conductivity by adding a small amount of graphene oxide, 0.05 wt % and 0.1 wt % for large-area graphene oxide and small-area graphene oxide which is 23.85 ± 0.23 and 29.21 ± 0.06 mS cm−1, respectively. The improvement may be attributed to the homogeneous distribution of graphene oxide, acting as an ionic conductivity promoter. Moreover, graphene oxide sheets with small area have lower bulk resistance as they can move easily through the gel with high amount of bound water, resulting in high ionic conductivity. Additionally, the GO containing gel has superior mechanical properties (tensile modulus of 2.77 ± 0.65 MPa and tensile strength of 8.33 ± 1.99 MPa) and high cyclic stability (retained 89% of initial specific capacitance after 2000 cycles) compared to the one without GO which makes it a potential candidate for use as gel electrolyte in flexible and wearable electronic gadgets.