A High‐Performance, Low Defected, and Binder‐Free Graphene‐Based Supercapacitor Obtained via Synergistic Electrochemical Exfoliation and Electrophoretic Deposition Process

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 5 V 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 ${{\tau }_{0}}$ ) 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. A green route to fabricate graphene‐based supercapacitor is developed by synergizing electrochemical exfoliation for graphene synthesis and electrophoretic deposition. The process can be overall performed in water‐based solvent. This integrated method obtains a high‐performance supercapacitor with high rate capability (82.31 % at 10 A/g than 0.5 A/g), excellent cycling stability (95 % after 10,000 cycles), and small time constant (9.73 ms).