All-Graphene Oxide Flexible Solid-State Supercapacitors with Enhanced Electrochemical Performance.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Flexible and wearable electronics require advanced energy storage solutions like supercapacitors.
• Graphene oxide (GO) and reduced graphene oxide (rGO) are promising materials for supercapacitor components due to their unique properties.
• Existing solid-state rGO/GO/rGO supercapacitors have limitations in capacitance for practical applications.

Purpose of the Study:

• To develop a flexible solid-state supercapacitor with enhanced electrochemical performance.
• To investigate the role of H2SO4-intercalated GO electrolyte/separator and pseudocapacitive rGO electrodes in device performance.
• To explore a simple and versatile fabrication technique for high-performance carbon-based energy devices.

Main Methods:

• Fabrication of a flexible solid-state supercapacitor using H2SO4-intercalated GO as the electrolyte/separator and rGO as pseudocapacitive electrodes.
• Utilizing a combination of photoreduction and electrochemical treatment for device fabrication.
• Characterization of electrochemical performance, including areal capacitance, rate capability, and volumetric energy density.

Main Results:

• The supercapacitor achieved a high areal capacitance of 14.5 mF cm⁻².
• High ionic concentration and fast ion conduction in the electrolyte, along with abundant CH defects in rGO electrodes, contributed to high capacitance.
• The device exhibited excellent rate capability due to efficient ion transport channels and high volumetric energy density (1.24 mWh cm⁻³).
• The unique structure offered extremely low resistance and high flexibility, operating in ambient conditions without external electrolytes, additives, or binders.

Conclusions:

• The developed flexible solid-state supercapacitor demonstrates superior electrochemical performance suitable for practical applications.
• The H2SO4-intercalated GO electrolyte/separator and pseudocapacitive rGO electrodes are key to achieving high capacitance and energy density.
• The simple fabrication technique and device advantages make it attractive for low-cost, high-performance carbon-based energy devices.