Nanoporous Carbon Materials Derived from Washnut Seed with Enhanced Supercapacitance

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Agro-waste valorization is crucial for sustainable energy solutions.
• Nanoporous activated carbons offer superior performance in supercapacitors compared to commercial alternatives.
• Developing low-cost, high-performance electrode materials is essential for widespread supercapacitor adoption.

Purpose of the Study:

• To synthesize nanoporous carbons from Washnut seed agro-waste via zinc chloride activation.
• To investigate the effect of carbonization temperature on material properties and electrochemical performance.
• To evaluate the supercapacitance performance of the derived carbons as electrode materials in aqueous electrolytes.

Main Methods:

• Washnut seeds were carbonized at temperatures ranging from 400-1000 °C with zinc chloride activation.
• The resulting nanoporous carbons were characterized for surface area, porosity, and pore architecture.
• Electrochemical supercapacitance was assessed using cyclic voltammetry and galvanostatic charge-discharge in 1 M H2SO4 electrolyte.

Main Results:

• Nanoporous carbons with hierarchical micro- and meso-pore structures were successfully produced.
• Optimal surface area (922-1309 m² g⁻¹) and pore volume (0.577-0.789 cm³ g⁻¹) were achieved at 800 °C.
• The 800 °C sample exhibited a specific capacitance of 225.1 F g⁻¹ at 1 A g⁻¹, with 69.6% retention at 20 A g⁻¹ and 98% cycling stability over 10,000 cycles.

Conclusions:

• Washnut seed is a viable and sustainable precursor for producing high-performance nanoporous carbon electrode materials.
• The derived carbons demonstrate excellent electrochemical energy storage capabilities, including high capacitance, rate capability, and cycling stability.
• These findings highlight the potential of agro-waste-derived carbons as a cost-effective and scalable solution for supercapacitor applications.