Fabrication of a Graphene-Based Paper-Like Electrode for Flexible Solid-State Supercapacitor Devices

Abstract

The increasing demand for portable and wearable electronics requires high reliability of devices for continuous miniaturization, and provides challenges for the dimensionally-confined bottom-up assembly methods which typically begin with materials such as graphene oxide (GO). However, GO based devices suffer from complicated synthesis procedures and lower device performance due to the presence of oxygen functionalities on the electrode materials, as well as the need to ensure a good interface between the electrode material and the electrolyte used. Here, a facile, two-step, top-down strategy was used to fabricate thin, all-in-one (PVA/H₃PO₄)/graphene/graphite paper-like electrodes. The assembled flexible, all-solid-state micro-supercapacitor devices exhibit excellent performance compared to previously reported values, such as a high volumetric capacitance of ∼3.6 F·cm⁻³ even after 20000 cycles. Notably, the devices also showed excellent rate performance with extremely high specific capacitance retention of up to 94% as the current density increased from 0.5 to 5 A·cm⁻³, indicating promise for high power applications. The paper-like electrodes were tailored to less than 0.5 mm width for further miniaturization and suffered from minimal capacitance attenuation. The excellent mechanical flexibility, capacity, and reliability indicate their promising application in energy storage devices.