Robust Brewed Tea Waste/Reduced Graphene Oxide Hydrogel for High Performance Flexible Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Tea waste, rich in phenolic compounds, is an underutilized resource.
• Graphene oxide is a versatile material for developing advanced composites.

Purpose of the Study:

• To develop a novel hydrogel composite from tea waste and graphene oxide.
• To evaluate the electrochemical performance of the tea waste/reduced graphene oxide (TW/rGO) hydrogel for energy storage applications.

Main Methods:

• A one-step hydrothermal method was employed to synthesize the TW/rGO hydrogel.
• The hydrogel's structure, mechanical properties, and electrochemical performance were characterized.

Main Results:

• The synthesized TW/rGO hydrogel exhibited a 3D porous structure and good mechanical strength (53.4 ± 4.0 kPa).
• The electrode material achieved a specific capacitance of 434.7 F g⁻¹ at 1 A g⁻¹ with 55.8% retention at 100 A g⁻¹.
• An all-solid-state supercapacitor using TW/rGO showed a specific capacitance of 372.8 F g⁻¹ and energy density of 12.9 Wh kg⁻¹.

Conclusions:

• The TW/rGO hydrogel is a promising, sustainable material for high-performance supercapacitors.
• Direct utilization of tea waste in composite materials offers environmental and economic benefits.