A High-Performance, Low Defected, and Binder-free Graphene-based Supercapacitor Obtained via Synergistic Electrochemical Exfoliation and Electrophoretic Deposition Process.

Abstract

An integrated electrochemical exfoliation and electrophoretic deposition (EPD) method is developed to achieve a high performance graphene supercapacitor. The electrochemical delamination of graphite sheet has obtained a low defected few-layer graphene adorned with oxygen-containing functional groups. Then, the EPD process produced a binder-free electrode to alleviate the graphene restacking problem. The electrode prepared using a deposition voltage of 5V exhibits the highest specific capacitance of 145.95 F/g at 0.5 A/g from three-electrode measurement. Moreover, this EPD-prepared electrode also demonstrates superior electrochemical properties compared to electrodes fabricated using PVDF binder. In the real symmetrical cell, the EPD-prepared electrode also shows excellent performance with a high rate capability of 82.31% (from 0.5 A/g to 10 A/g), high cycling stability of 95.00% (at 5 A/g) after 10,000 cycles, and rapid frequency response with short relaxation time (τ₀) of 9.73 ms. These results indicate that this integration method is beneficial to construct a high performance binder-free supercapacitor electrode consisting of low-defected graphene materials, low electrode resistance, and less agglomeration of graphene sheets by utilizing an environmentally friendly process.