Flower-like nickel hydroxide@tea leaf-derived biochar composite for high-performance supercapacitor application

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• High-performance energy storage devices are crucial for next-generation power sources.
• Developing sustainable and renewable materials is essential for environmental and economic benefits.

Purpose of the Study:

• To synthesize and characterize a novel flower-like nickel hydroxide/spent tea leaf-derived biochar (NiNF@TBC) composite.
• To evaluate the electrochemical performance of the NiNF@TBC composite for supercapacitor applications.

Main Methods:

• Synthesis of tea leaf-derived biochar (TBC) with a high surface area (1340 m² g⁻¹).
• Fabrication of NiNF@TBC composites using TBC as a support for nickel hydroxide (Ni(OH)₂).
• Electrochemical characterization using three-electrode and symmetric supercapacitor configurations.

Main Results:

• The NiNF@TBC composite exhibited a specific capacitance of 945 F g⁻¹ at 1 A g⁻¹ with 95% stability after 10,000 cycles.
• A symmetric supercapacitor using NiNF@TBC delivered 163 F g⁻¹ with energy density of 19-58 Wh kg⁻¹ and power density of 826-6321 W kg⁻¹.
• The composite demonstrated excellent long-term cyclic stability (94% after 10,000 cycles).

Conclusions:

• The porous and hierarchical structure of NiNF@TBC enhances ion and electron transport for superior energy storage.
• Utilizing agricultural waste (spent tea leaves) as a green carbon source is feasible for creating advanced nanomaterials.
• The NiNF@TBC composite is a highly promising electrode material for green and sustainable supercapacitor applications.