Bipolar Exfoliation and in Situ Deposition of High-Quality Graphene for Supercapacitor Application

Developing a reliable, simple, cost-efficient, and eco-friendly method for scale-up production of high-quality graphene-based materials is essential for the broad applications of graphene. In this study, bipolar electrochemistry concept is utilized to design a single-step and controllable process for simultaneously exfoliating a graphite source and depositing both graphene oxide and reduced graphene oxide layers on conductive substrates. The electrochemical analysis carried out on symmetric cells revealed an areal capacitance of 1.932 mF cm–2 for the high-quality reduced graphene oxide deposited on the negative feeding electrode, and 0.404 mF cm–2 for the graphene oxide deposited on the positive feeding electrode at a scan rate of 2 mV s–1. The devices also showed high stability for periodic and repeated constant current charging/discharging cycles which is suitable for energy storage in supercapacitors. In the frequency domain, cutoff frequencies of 1820 and 1157 Hz at −45° impedance phase angle were obtained for the positive and negative feeding electrode-based devices, respectively, which is a promising characteristic for alternating current filtering applications.